I am new to making- I would like to make a simple 3D 90 degree angle with a 105mm high by 155mm wide surface to affix various warning stickers to on machines at work. A mini billboard would best describe it. The base would need to be 50mm, and a 2mm thickness overall. It should be simple to create, I just don't know how to get started. Any help?- Simple drawing attached, Thanks!