There are many ways, but for me the simplest is to attach the spinnaker halyard to the dinghy.
I attach a bridle to two attachment points on the stern and one on the Bow. Then I attach the spinnaker halyard to the bridle. I empty the RIB of all gear and any water. I then haul the rib up and guide it over the life lines to rest on the bow. Some owners have built deck cradles to hod the RIB on the fore-deck. Since mine is an inflatable, I deflate the dinghy and roll it up securing the package on the cabin top. My boat weighs in at about 38 kg