You have a few issues here:
1- No system info (Gotcha-free [Asterisk-GUI] or Piaf-Color w/ FPBX) - we need to know
2 - IVR in FreePBX is straight forward (GFA-GUI - I don't have yet so can't advise - I need to learn this one myself)
3- The after Hours message is a CFC or TC/TG your choice (CFC=Call Flow Control [read Day/Night Modes] and TC/TG = Time Conditions/Time Groups) I find CFC easier for me (one code to remember).
So without knowing #1 assuming FreePBX
Let's tackle #2 here:
A - Login to the FPBX Admin panel and Applications->IVR
B - Add a New IVR. Give it a name and description
C - If you have the announcement for your IVR made, place it in the announcement pull-down.
C.1-Direct dial is a list of directories for your extensions. If you want callers to be able to dial an extension directly in the IVR chose default or create a new directory (Application->Directory) with just the extensions you want allowed -- or disable it completely so only menu options can be selected
D - Timeout of 5 is fine (if no digit pressed). Invalid Retries of 1 or 2 is normal) read the blue dot for more info on the other options in this section (so this post doesn't go on forever
but the Time out Destination is where you put the person if no key is press ed as Extension 101**
E - In the section IVR Entries is where you would put your options
E.1-Ext is the key the person can press0-9 # and * are acceptable (in older versions i and t (Invalid and Timeout, respectively) could also be used but now are done above this section. Destination (2 parts - 1st is a list of destination types and 2nd is options within that type. i.e. choosing Extensions will list extensions on your system to choose from)
So if you want press one to play our hours of operation, press two to get directions to our office or press three for a receptionist, then the lines would look like this:
1 Announcements Hours of Operation*
2 Announcements Directions to Us*
3 Extensions 101**
99 Feature Code Admin 1:CFC Switch***
* Announcements are made through Admin->System recordings or if you have GoogleTTS set up (I use the old PWhite TTS which works well with GTTS
Make the recording and then go to Application->Announcements to make this available to the IVR. The Hours of Operations and Directions to us were example names for your announcements.
** 101 assumes your operator/receptionist extension - adjust to your schema
*** This is two parts -- 99, yes more than one key can be done (I use *0 for a company Directory or if you want "hidden" options, as I did here for your "after Hours" section below.
F - Click Submit and Apply Config
Now to your After Hours
Applications->Call Flow Control
-Call Flow Toggle Feature Code Index (0-9) [last digit only] the whole code is *28[this index#] assuming 1 from 99 above.
-Give it a Description (e.g. Main Day/Night) [or from the 99 option above CFC Switch]
-Current Mode can be left alone [should read Normal(Green/BLF Off) ]-- If you have a phone that can show BLFs varies by Manufacturer on how to set these up. [The other mode is Override(Red/BLF On]
-Recording for Normal (Green) Mode: Default is nothing as your IVR will handle that
-Recording for Override (Red) Mode: Default is nothing again as your Afer Hours destination Should handle it for you
-Optional Password: Set it if you want only a few people (say yourself and a receptionist to be able to switch on/off) but you must make sure you remember to tell authorized people what it is (I don't use it because I don't need it now) -- with the "hidden 99 option" above a password may be a good idea in case someone accidentally guess this option.
Normal Flow (green) Destination would be your IVR for Normal business
Override Flow (Red) Destination would be an announcement for your after hours message
Click Save and Apply Config and your all set.
Now on your inbound routes (Phone numbers, point to the Call Flow Control, Submit, Apply Config again and your done (Except for making the announcements of course [Which I would do first before any of the IVR and CFC stuff])
Announcements are in Applications->Announcements
-Description -- The name of your announcement
-Recording -- These are System Recordings. Either use your phone or read how to make them offline and upload them but make them available to this module (Even GTTS wav files need to be made accessible to be used here)
-Repeat -- Do you want people to be able to repeat the message if needed? if so tell them which key to press in your message (e.g. 'to repeat these directions again press Pound' -- and select pound key in this drop down list
-Allow Skip: is a yes / No type answer but doesn't give an idea of which key would be used to skip the message, so I'd leave it off anyways (unchecked)
-Return to IVR: is another Yes / No type answer (good for your IVR options 1 and 2 which if done correctly can ONLY be accessed by the one IVR [read the blue dot for some caveats on the return to IVR option being used])
-Don't Answer channel can be left alone UNLESS you need it based on the Blue dot information (just leave it be for now)
-Destination -- this is where the call goes after the announcement is played. You can send it back to the Main IVR manually by choosing IVR ->Main IVR (2nd box appears after you choose an option in the first one)
Now for your after hours message you could have it go directly to the receptionist's Voicemailbox by Choosing Voicemail in the list and the extension (101) in the 2nd box (VM has 3 options per extension -- Busy - Unavail - NoMsg. Busy I use for normal hours as if I'm on the phone and give the VMX locator a chance to use FollowMe whereas my Unavail(able) message says to leave a message and NoMgs is no message at all just a beep (which you could incorporate into your after hours message (impersonating a VM message [e.g. After Hours Message, to leave us a voicemail at the end of this announcement leave your name and Number with your messasge and we'll call you back as soon as possible" VM-101(nomsg) [BEEP])
- Submit changes, Apply Config and you're done
I hope this is more than you needed to accomplish what you asked for. The Time conditions and Time groups, I have never used so if that is the rout ou want to go, someone else will have to step in or just use the forum search tool for posts on the subject.
Good Luck and Welcome to the Piaf Forums.