Well, it's a Yerf Dog so, that's a good start...
IIWM, the first thing to do is check that the engine runs; having sat for 5+ years means the fuel tank & carb will need to be thoroughly cleaned, fuel lines replaced as well as the spark plug, oil & air filter... wait, does it
have an engine?
Next, check all bearings, front wheels & rear axle; apart from being worn, by now, some may have seized...
Of course, those tyres will need attention; again, having sat for so long, they may now be useless; flex them & check for cracks...
Apart from that lot, it's just clutch, chain, brakes & controls... plus checking every single nut & bolt for condition & tightness
Please add more pics from the rear; we'll be here to help if/when you need it...