Hello there klice_elite, ‘CHANNEL’ is meant to represent the streamer (in this case, you) and the specific ‘USER’ following you.
If your twitch channel is klice_elite, and I am following you, then the URL will look like the example below: https://apis.rtainc.co/twitchbot/following?channel=klice_elite&user=tabzAstoria
To automate this in a command, you can use the following:
!addcom !following $(touser) has been following for $(customapi https://apis.rtainc.co/twitchbot/following?channel=klice_elite&user=$(touser))
If you wanted to view how long a user followed your channel for, you may use
!following <USERNAME> (where ‘username’ is the syntax), this will display the prompt > “USERNAME has been following for (e.g.) 8 months, 3 weeks” | or the response “USERNAME is not following” (in respect of their current status towards your channel).
Hope this helps!