Use whatever is to hand to form the wreath base eg: Wire Coat hanger, Thick cardboard, Polystyrene or buy foam pre-moulded forms or weave some twigs etc. So long as it will take the weight of you decorations.
Then you can either stick or bind with string or wire onto the wreath your decorations. Make bows to fix into gaps, and a large one for the top. Best wishes.
I buy a wreath form at the Dollar Tree. Then add mesh ribbon in large loops. Embellish with small ornaments.
Here are some ideas from dollar store supplies: https://www.frugalfamilytimes.com/2019/11/dollar-store-christmas-wreath-ideas.html?m=1
Hello. I saved this interesting wreath links they might be helpful
If you fancy something a bit different here is a star one