Welcome to the forum, zip.
You have three threads asking different but related questions, but provide no information about what you want or have planned: take it one step at a time.
The first step is to decide what you want: what size, where will it be driven, what style of kart: there are so many variables it just isn't funny!
Have a look at some images on google & here, get your mind set on something then tell us about it.
BTW: if you want to build it from scratch, don't go nuts on a design