Rebuilding

I have a 99 trx 300ex I’m working on it had bad rings I bought rings and as I was replacing them I noticed on the very bottom oil ring spot I have a chip out of the piston it’s only on the oil ring spot will the rings keep oil from slipping through the spot or will I need a new piston and also when I was putting my top ring on it will not seat properly in its spot are they hard to get to go in there slot or is there probably something wrong with it I have no clue I just need some help I’ve never worked and a four wheeler before I usually only ride dirt bikes but I thought I would give this a try please help if u can