I’m running FreePBX 18.104.22.168 and Asterisk 22.214.171.124. After 5:30PM, I would like phones to ring twice, then go to voicemail. Is this something I would do in the FreePBX admin web GUI, or individually on each phone?
You would use the FreePBX GUI.
Look at time groups and time conditions. This will allow you to route calls on time. After that send the call to a ring group to ring phones for a few seconds and then send it to voice mail.