ok. i found my solution... polygons / tool options / keep faces together.

that did the trick!

ok i pinpointed the problem, when i select the edges and extrude (even on the first time), it is duplicating the vertices as well. i watched how he did it 10 times and im doing it the exact same...

actually... when I extrude the edge, after once or twice the problem arises... If I select one of the vertices at one of the points (where it appears as though there's only one) there are actually 2...

Nevermind... Out of desperation I decided to select each area around each of the vertices and merge them, just to be sure there wasn't any other vertices very close that I didn't see - and it worked.

I'm receiving that error at the section in the tutorial where you're deleting 4 borders which make up the end of the wrist. I'm doing it exactly like the tutorial.

If I only extrude once and...