I have only done two scratch artworks both were on Ampersand scratchboard so I have no advice for paper. For tools I only used the pointed knife tool you can do a lot with just that one tool.
I'd recommend the same way I started a 3pk of Ampersand scratchbord in 6x6 and a single pointed knife. I think there would be a high chance of getting frustrated with paper or cheaper quality boards.
I would also recommend picking a subject with a lot of contrast and interesting light and just jumping right in no practice lines or boards.
Here are my first two attempts 1) tiger 2) owl both done on 6x6 boards with the tool you see on the owl board being the only tool I used.