3020 cnc quick guide

Hi.
Long time after my last post... had 2 babies, little time to diy.
I bought 1yr ago a 3020cnc on eBay to cut simple holes (iec panels connectors/xlr connectors/vu meters cutout) but in little spare time I've now I manage to engrave easy shapes without understand how to set depth to cut panels.

I use:
- front panel designer to generate dxf files
- open mach3 with lazycam and import dxf
- export g code from lazycam and start mach3 to route

In lazycam I can't find how to set depth of cutouts (in forums I found that I've to set max depth but I can't make it works)and how to edit dxf imported file in lazycam to make multi route of the same shape to cut the panel.
In my little spare time I haven't found a well done and easy tutorial to make this and support from the CNC's seller was nothing...

I only need to know how to set panel depth and to make a "multi pass" route to cut a 3mm alluminium panel.
Also a already done g code sample or lazycam file was useful for me to understand how to make them.

Thanks for help,
Alex