This thing is a stand for an electric unicycle (EUC). The printable parts are connectors used to assemble sections of 1x2 lumber into a rigid, self supporting frame.
You will need print supports for one of the pockets in each part. There are three connector types.To complete the frame you will need to print: 4 shoulder connectors, 2 type-A feet, and 2 type-B feet.
You will need about 5' of 1x2 lumber (3/4x1-1/2) cut to length.
For my Kingsong 16X I used the following: Six 6" sections for the uprights and bridge pieces and two 9-1/4" lengths for the lower cross-members. The wood should require firm force to fully seat in the connectors. If the fit is too tight a light sanding may help achieve a perfect fit.