I’ve been there too! When I applied my frosted windowfilm, I learned that the order really matters. First, you have to clean the glass super well and dry it completely. Then, spray the window lightly with water mixed with a little soap — it lets you reposition the vinyl if needed. After that, place the vinyl and use a squeegee to push bubbles out from the center toward the edges. This method is explained nicely on
https://applyityourself.com, especially for tricky spots on windowfilm. Following these steps helped me avoid bubbles every time.