Hey, welcome to both of you! Enjoy the resources of this forum and feel free to post a photo or two when you are comfortable
Originally posted by grnhrn Will I need to get some kind of adapter for K mount or 42 mm thread mount?
K-mount, no adapter needed. But if the lens is older than AF, it won't have AF (might still allow catch in focus, aka focus trapping). If it is older than auto-aperture, it won't have that (auto aperture is when the aperture is selected with the dials on the camera body, instead of the aperture ring on the lens).
m42 needs an adapter, but it is glassless so there is no loss in quality. You can get really cheap adapters online, but if they are poorly machined they might prevent focusing to true infinity, or even (worst case scenario) get stuck. The genuine Pentax adapter is the best one, doesn't require any tools and its safe.
Here is one of the threads that explains using older lenses in more detail:
https://www.pentaxforums.com/forums/54-pentax-lens-articles/110657-how-use-me...k-x-k-7-a.html