stikpilot welcome!!

first, the wheelpants are kinda small and i didnt use them and wouldnt at least untill i beefed up the landing gear because they will sheer off clean after the first hard landing but that is an easy repair, just need a little white ultra coat, but they will go right thrrough the wing bottoms if on when the gear goes, but back to your question----you need to put the tire and washer in the pant then slide the pant and wheel over the vertical axle and then with the collar on your driver already pry it open a little and insert it and tighten, shewwww i know its a little tight but it works

sounds like you will have a nice setup with the rest and you will have a ball with this plane[8D]