conquer an island

Your troops will automatically embark onto convoy ships when moved into sea terrain.

Still, I move my troops (infantry/tanks . . . ) to the sea, but nothings happens!!!

like this:

Your units are embarking. This takes a while, but once they finish, they will turn into transport ships. When they arrive, they must disembark, which takes a while as well. Then, they will turn back into land units.

The struggle is real... if you know what I mean