Yeah man... you gotta use the putty.
Keep tightening the displosal until you see putty oozing out around the entire
peremeter of the flange.
Wipe off excess. Tell tennant not to use that side of the sink until the next day to give the putty some time to set up a bit.
**Also, buy/bring some rubber gloves, since it's not a new disposal... that shit will be nasty.
God bless the internet. LOL.