Starting the recording is fairly simple. Note that you will need to login to Focalscope with a supervisor account and log into the phone with the same account.
1) In the Telephony module > Sounds
2) When creating a new recording with type custom file, click on record.
3) It will ring the phone that the agent is logged in to. Once picked up you can start recording and press # to end.
4) Set the name of the recording and press Save.