"FT8 properly" means in what manner?

FT8 is in cqrlog's mode list, so it can be selected from mode selector. How ever if you use rig cat and have "auto" checked to get the frequency and mode from rig you can not have mode as FT8 as rig does send that. It sends either USB or PKTUSB or similar depending on your rig brand.
If you set "remote for wsjt" on then you can get mode as FT8 (or other) as the wsjtx or jtdx will send that mode to cqrlog, not your rig.

See your cqrlog/help for further information.
There are also some videos at https://www.youtube.com/channel/UC3yPCVYmfeBzDSwTosOe2fQ