Bitmaps are a raster style of file, so the interface is going to try to engrave it. It will cut vector files.
There are a few tutorials that can help you out, if you’re willing to take a little bit of time to read through them. It might save a lot of wasted time trying to figure things out.
Since I don’t know your familiarity level with design software, I’d recommend starting with these three, and if you have time, there are a few others that can help too. The link to the Matrix at the bottom has a lot of good tutorials for designing for the laser.