1, you may want to move this to the flow sim section. you can do that with the advanced editor in the top right hand corner when you're editing your post.2
2. there are a couple discussions about this you may want to check out
3. general procedure is to make the FPGA or other electronic component a block and apply either a surface heat generation rate or volume heat generation rate to the component. for material, apply the material it is mostly composed of. from there you can add whatever complexity you want based on the info that you have. break it into a multibody or assembly so that you can apply more materials to it or more closely match how the heat is added. look at things like 2R model..etc.