Hello and welcome!
Based on this and your other recent posts, it sounds like you are just getting started trying to figure out how to use your Glowforge. One of our forum regulars has a couple of posts that covers much of what you need to know getting started:
Those are a good place to start to get answers to the questions you are asking about masking and settings. There is lots more information in the forum. The search feature can be useful (magnifying glass in the upper right corner).
Regarding your request for @rbtdanforth’s design files: there are a variety of reasons someone may not want to share design files and, it can be uncomfortable for some to have to say no publicly. So, our community standard (and forum rules) are to not ask and, leave it up to the designer to offer. There are quite a few files freely available (for personal use) in the Free Laser Designs section.
You are, of course, welcome to post questions but, looking at the answers already posted are likely to be faster than waiting for someone to respond.