Notice how the launcher only loads Vanilla Minecraft? This is my bad and I will update the modpack later to eliminate this issue. Meanwhile, install the modpack and open the directory by clicking on the modpack settings and pressing open. Once you get here, you click on the "modpacks" folder, then the "extreme overhaul" folder, then the bin folder and rename the "forge-1.7.10 -10.13.4.1558 -1.7.10-universal" file to "modpack." (This is case sensitive.) Reinstall the modpack from Modpack Settings and you'll be good to go. Thank you and enjoy!