Rest the lugs on your forefingers and try to push the crystal/case out with your thumbs, it should come out that way. Then you can use a case back opener to prise the crystal/case apart.
Here is my Surf King from the 1960's. Very similar to your watch.
Here it is with the crystal removed, showing the case back and movement. Please note that the stem is in two parts, and the male part is easily lost so beware when removing.