You can print all parts without supports, infill 20 percent is more than enough. To complete need 2 bearings per wheel, and 1 nut M8 with length of 70mm at least. To join parts together I use M4 bolts with nuts.
if you need washers, see https://www.printables.com/model/1089868-washer-1mm-thick-inner-diameter-81mm-outer-diamete
The author marked this model as their own original creation.