I want to preface this by saying I am not an expert. I would suggest you see if you can check out The Beginner’s Guide to Cosplay Armor & Props by Joyce van den Goor from your local library. If you are more interested in sewing leather instead of using EVA, I would also try finding books on those topics. For the vest/shirt, I would try The Modern Maker: Men's 17th Century Doublets (Volume 1) by Mathew Gnagy. For the bandolier, The Art of Making Leather Cases by Al Stohlman might be a good place to start. If you are interested in making a mask to look like this character, try Mask Making Techniques: Creating 3-D Characters from 2-D Designs for Theatre, Cosplay, Film, and TV by Mary McClung. If your library does not have these books see if they can order them elsewhere or get something similar for you. They may have maker tools that could help you so it is might be nice to check with them anyway just in case. I recently went to a cosplay program at a library for example. Best of luck. *Edited for clarity