I've been wanting to try playing modded minecraft for a while now, and finally tried. I started off with downloading Forge, Optifine, GSL Shaders and a shaderpack. I installed Forge and GSL Shaders, ran Forge, then GSL Shaders, and added Optifine to the mods folder and the shader pack to its folder, and ran Minecraft. Everything worked perfectly. I then tried adding a mod, Iron Chests for 1.12 to try it, and crash. Tried a few other mods to no avail, and tried with and without Optifine. Went so far as to uninstall Minecraft, delete the .minecraft folder and do a fresh install and just download Forge for 1.12, the mod, run Forge and add the mod to the folder. Instant crash. I'm running Forge for 1.12, Java 8.131 x64 on Windows 10, and have Minecraft selected to 1.12 (obviously). The launcher says "An unexpected issue has occurred and the game has crashed. We're sorry for the inconvenience." I can't figure out what is wrong or what I'm doing wrong as I've never done this before, and everything I search seems to be a case by case basis. I included the fml-client-latest file. Any help is appreciated, and I apologize in advance if I'm just a noob.
fml-client-latest.log
