I believe that anyone new to the sport should invest in a complete competitive racing kart at first.
There’s too many unidentifiable parts and pieces to assemble one from scratch.
Do your homework to make sure the kart you buy can be raced locally, (even though you may want to just drive it for a while before you jump in to racing).
Karting can be the most rewarding thing you ever do, but if you do it wrong it can be a waste of time and $$.
Start with something semi simple like a LO206, KT100 or KPV. Learn how to drive it correctly and maintain it – then learn to tune it to fit your driving – then learn how to race and learn racecraft, before you decide to buy a TAG or shifter kart
I believe that if every new karter took these simple steps, there’d be more Karters and less worthless stuff on CL.