Sketchup with Sketchucam is what I use for most flat parts I build. If I am building complex parts, I like to use Fusion 360. Both of them have great video tutorials available. Sketchucam has it's own help section that tells you how to do things. There are forum threads (CAM) on this website that can be searched for more information and they are also in the Resources section.
You need something that is capable of creating a vector file like autocad, onshape, fusion 360, illustrator, inkscape. Then you need something that can take your vector file and generate the gcode to do the cut you want such as estlcam, fusion 360, etc. Some of these will do both the CAD and the CAM there is a lot of free stuff and expensive stuff out there. Which software is best depends on what you want to do like a mechanical part or something more artistic a 3D carving? Be more specific with what you want to make.
I expect that I will want to do mostly 2D work such as "engraving" type projects in wood then filling with wood or epoxy. Is there a software program that will allow a design to be cut into a board then switch to cut the same shape in a contrasting material to fit into the first cut? Basically software that will do both cutout and inlay portions of marquetry.
Check tehe SOFTWARE link at the top of the page.... (Draw in inkscape/sketchup/any other vector application -> Export as DXF or SVG -> OpenBuilds CAM -> OpenBuilds CONTROL )
Another option is F-engrave. I like it for V-carving. The price is mostly the reason. But the following process can be used for any software that can engrave like the OpenBuilds software. For larger objects, you can use a band saw. V-Carve Inlay Using F-Engrave