I'm a first time mod user and rather dumb when it comes to software, so please explain in little-kid language so that I can understand.
I downloaded and installed Forge 1.11.2 first. I tested it by opening Minecraft in the Forge profile (I think that's what it's called, the thing on the launcher where you select Forge?) and it works fine. Then I realized that the mods I want are all 1.7 and 1.8, so I also downloaded a previous version of Forge - 1.7.2-10.12.2.1121. That Forge works ok too, but only by itself. When I drag any mod I want into the mod folder, the launcher works fine, but the game never comes up. I don't even see a crash message.
I read the rules, so I would post a crash report if I could find one. I'm not sure there even is one. I'm trying my best, but I don't know what I'm doing. I realize there is probably a really easy fix for this, but I don't know what it is. Help?