tried reading that but not sure by all the part lists weather rear left axel is required i assume it is but not sure, they could of wrote that pdf better for example left rear axel and right rear axel so that way i would know there's 2 parts 1 for each side, when I try driving the car it does not move the motor spins the lil cog and no movement is this because of missing Axel (left rear side)? or another issue?

However digging around online i found this pic (image link)

ibb.co/hHZWVm

the parts I need to know the name of is 3rd up from the bottom right (metal silver) what are these called please?

I know 1 is called BA16 (SHORT) AND 1 IS BA17 (LONG) do anyone know what 1 goes on the rear left isit the short or long (rear wheels facing you)?