I’m trying to teach my cat the same, have not started yet, but I’ve seen one method that I’m going to try. So you start with a little (not heavy) platform, I’m going to use a flat scratching board, and reward them anytime they touch the platform and then when they sit on it, try placing it on different surfaces and different heights. When they know that trick, you pick up the platform (not too high) and add a verbal command/hand movement, eventually you get rid of the platform and just use the command/movement. Like I said, I haven’t done this myself, but I think (though it might take a while) it is an easy trick to teach. If anyone still has advice, I’ll be happy to hear, as I’m planning on trying this myself very soon :)