the concept of the project is you do the work yourself instead of going to a workshop.
engines are easily available.
you need to define your budget. look for sponsors if you cant afford. this is not a cheap enterprise.
you need to look at the ATV market nearest to you. thats where you will find most of the components such as axels, wheels, drivetrain components, chassis parts. some items you can get from old atvs some you will have to fabricate