I think the limit is now 500 lines of G-code, so that won't stop you getting it going.
On the last page you can disable the axis you don't want to use.
On the last diagnostics page, make sure your reference switches work the appropriate in port indicator lights. It won't reference if is is past the stops on an axis. The Z-axis must reference first with ref all. On last page you can do any axis on it's own.
To change direction on X-axis swap ONE of the winding connections, A or B. to reverse it.
You probably have the soft limits on, and it won't work too well that way if not referenced. On first page make sure Z inhibit is not set so that z axis can't move.
Learn how to get each axis at the middle of travel then zero each axis to ensure it's not off in the weeds.
The Mach3 manual machine setup instructions if followed closely will go a long way towards making everything work.
Crawl before you walk. Stops crashing into thing by accident.
Keep experimenting and learning.
It is better to analyze each problem, fix one and move to the next.
Trial and error due to many non-operating combinations will cause frustration. Don't blame Mach3. Only the setup and the wiring.