I’m very new to building/assembling derailleur and shifting components. I have a cdhpower frame with what I call a “track” style for the rear wheel to be accepted into. I would like to build this bike to shift. Does anyone have any advice on what components I need to get from a-b as far as setting up a rear derailleur for a 5 speed freewheel. I have included a pic below as to the style of dropout I have. (Technicaly not a dropout?) basically I don’t know if there is a direct bolt on setup or do I need to fabricate something for the derailleur to hang on to?