Oh no, this block is just my cursor, ther is nothing at all
Sorry that you have trouble with this:
Step 1)
Click the "create ship" button in the bottom right
Step 2)
You should see a white rectangle while moving the mouse, drag that somewhere in the green zone
Step 3)
Click somewhere in the green area and a new ship with one block should appear.
if this still fails, try making a new account or I can reset yours, let me know :)