Make the base for the legs to attach to and the suitcase to sit on. Measure the suitcase and then cut the piece of plywood slightly smaller (about 2/3") than the suitcase.
Attach the legs/axles to the four corners of the plywood and attach two L-brackets to each leg, then screw them into place.
Miter cut the edge to fit the edge of the plywood. Measure inside to get an accurate cut. Glue and nail the trim in place and on the legs to help stabilize them. Pass the nails using the awl..
Paint or seal legs and base (if old paint, follow lead rules). Fill nail holes with wood filler and paint over.
Raise the base and place the suitcase on top. Open the lid and screw the case to the base with screws that will not pierce the width of the wood below.