There's a variety of ways you can go about making the wings removable. Bottom wing would typically attach the same way most basic models do. A pair of nylon bolts near the TE Center and a wood dowel or ply tab on the LE Center that plugs into a socket in the fuselage bulkhead.

Top wing then is nothing more than bolts that hold the wing to the struts. Depending on the make up of the struts will determine the attachment method. Typically there's a 90 degree metal tab on the strut. Each part of the tab has a small hole drilled into it through which a bolt will go. One bolt holds the tab to the strut and the other to the bottom of the wing. If the strut core is piano wire, the tab can be wrapped around the wire and soldered to it. Again, lots of ways depending on the make up of the struts. You'll also need hard points in the wings at the strut locations. Keep in mind too, accuracy in building the struts, especially the center ones, determines the incidence of the top wing. Must be as dead on as you can make it or flight characteristics could be impacted.