After creating a project have you added a new table using the + at bottom left of the tables tab.
If so have you added data fields from the data types tab.
When you have done this go to pages and add the layouts you need, this is what displays your tables.
Then open your collection layout, click on fields and drag in what you need.
Then open your item layout add a form from the bricks tab then drag your fields there.
Should work from there.
P.S. Don't forget to save the table before going to sandbox, I fell for this a few times.
