poor cutting results

[Tosho82]

Hello there, I'm Tomislav from Croatia, electrician and am working on plasma cutter and laser cutter.

Now I started to work on chinese CO2 laser with 280w yongli tube and off course didn't get any feedeback from seller.
It's about cutting stainless steel and all that I've cut has terrible, burnt edges so, I'm wondering if here is somenone who works on that kind of machine to tell if this is ok or there's something wrong and to check how to get the best of the machine with cutting everything else.
I mean, on this kind of machine can I get better results or this is the best I can get?

Here are some pictures of the machine and cutting results.

Thanks everyone in advance, regards.