I wanna get better at building on Roblox Studio, how? Also what does Meshes do?
WIth building, practice makes perfect! Try to experiment with different stuff like unions and welds, and as you get better you may want to move on to more advanced things like constraints, joints and meshes.
I found free models to be a great inspiration to me when I was a beginner, and in learning how they were made, I advanced my own skill in building and scripting! If you find something you don't quite understand, look for help online on the DevForum, this website, YouTube or any other site.
Meshes are geometric models that can be imported from a variety of outside programs, for example Autodesk Maya and Blender. I use them sometimes when I want to use an outside model from a video game - for example a motorbike or vehicle.
Make sure that you don't spend to much time thinking about building too much or you will just be like me, I used to always worry too much about building I spend to much time just overthinking it and I wasted a lot of time so my tip is just to build something right away don't spend to much time overthinking it! Good Luck!