Go shopping in your local Home Depot or Lowes or similar. The connections between toilet and tank are stock plumbing items. The tank likely has a large female threaded piece on top. Vulkem on the threads to seal when you assemble. The toilet uses a standard toilet mounting system. What you are looking for is a match where you can screw the adapter into the tank and then put the toilet mount into that. A sponge rubber seal goes between the toilet and the mount. In the case that the toilet mount and the tank adapter are slipped together, use vulkem to seal the two together. Be careful with heights here as the toilet has to sit on the 'floor' (the toilet perch). Sitting above the floor will lead to an unsteady throne. Sorry I don't have pictures, but I never thought it was something someone would want to see.
1978 Argosy 6 Metre Minuet
2006 Toyota Tacoma