Welcome to the forum.
It sounds like you're having the most common problem of chain alignment/tension.
If you're using the kit supplied chain tensioner the bracket probably needs to be bent/twisted so the tensioner wheel aligns with the chain and the bracket needs to be secured to the chain stay so it can not move and let the tensioner get into the spokes.
You'll want 1/2 to 3/4" slack in the chain measured on the top run with the bike being pushed forward.
Use the search feature at the top of the page, type in 'chain tensioner' for hours of reading on this subject.
Good luck. We're here if you need more help.
Age and Treachery Will Always Triumph
Over Youth and Skill & "Charlie Don't Ride"