It's not really a tutorial so much as a list of instructions. The system is fairly intuitive so you should have no trouble, however you should probably read it anyways just to be sure. It is timed, however you should be able to read it within the limit and that timing is separate from your actual test sections.

The GMAT Prep software gives you a good sense of what it will look like, except in the Prep there is no time limit.

You don't get a break between the AWA essays. If I remember correctly, you will get another instruction page (probably timed as well). You will have a full 30 minutes for each essay.