I am looking to paint my garage under my apartment. Its a fairly large (for an apartment) garage (37m2)..At the moment its dark and dinngy looking place and I wanted to lighten it up a bit ( Its going to double as gym / time away from the missus area

At the moment its bare brick all the way round. Should I seal it with concrete sealer first ? I also have a heap of taubmans tradex ultra prep laying around ( wallboard sealer ). Would I be able to use that ?
What would be the best way to paint this dark cave to give it a bit of life.. ?
I was also looking at painting the floor as well.. I was thinking a light grey paving paint.. Any ideas on that as well ?
Any ideas / comments would be greatly appreciated
Regards,
Cam