I put a new ssd into the Mac and tried to boot into usb didn’t work

I first started using the command r but it just brought up a white screen then I tried to make a bootable usb from a 2015 MacBook Air running high Sierra I believe and from what I know it looks like it worked well and it is a bootable drive. But when I try to use it and press Option and turn on the Mac it shows the usb and I press it and a question mark and for 10 seconds then turns off. I tried to restart my memory (I think it was like shift+command+r) or something like that. Nothing still. I looked at the mother board and nothing looks disconnected all cables from what I could see look fine. If you think it might be anything let me know and I will try it. I head that some MacBooks need to use a disk instead of a usb in order to work. I just didn’t want to buy one before I know that’s the issue.