This post is mostly for myself :-) This was very simple years ago; actually it was automatic. Now, I have no idea why, but shared directories are not automatically mounted anymore. By searching online it is incredibly difficult to find a proper answer: I tried a million answers but none was working properly. The only one that worked is simply the shortest and the one I never remember for some reason (and also difficult to find) :-):
this is how I do it, and it works for me. No idea why the other techniques are not.