Here's one approach to installing hardtail adjustable bridges. This is the most basic way of doing it, by screwing it through the top the box to the neck stick (with wings added to take the fixing screws). This method uses the "top loader" holes at the back of the bridge to anchor the strings, rather than drilling through the body do "through body" stringing, which is more difficult to do.
https://www.chickenbonejohn.com