Hi Faszero,

Welcome to the forums.

To convert a CAD model into something for the machine to create, you need a CAM package, such as Vectric Aspire (or one of their simpler and cheaper other products) or Fusion 360 (free for hobbyists, very capable, slightly bigger learning curve). There are millions of videos on this topic on the old youtube - go have a search for tutorials to get the idea.

Very envious of your space! I've got access to an old BP, but no space to bring it home with me unfortunately... :(

You can get turret mills which already have CNC capability, and buying used is probably the cheapest and most sensible solution. Having said that, we're not on this forum because we like taking the sensible option, so there is plenty of information about conversions in both the milling machines area of the forum, and the bridgeport forum in particular.

Happy milling :)