How to Build a Modpack
I'm creating this since there's quite a few of you guy posting in my comments/issue tracker that really don't know how to do this. Please read this page in its entirety, as it will help fix a great many problems; not just those related to Redstone++.
Step 1: Install a Launcher worthy of making Mod Packs.
Basically, go download MultiMC, if you don't have it already. https://multimc.org/.
The vanilla launcher is fine if all you want is OptiFine, but you'll start running into issues as you start building more and larger packs.
Magic Launcher, by default, likes to inject mods into the Minecraft .jar. This is a very old, and very outdated way of installing mods. You do not want this. You will get crashes. They will be very strange errors. And those errors will confuse whatever modder you send them to.
Step 2: Get a UTF-8 Complaint Text Editor for editing Configs.
Mac users can just use Textedit.
UNIX/Linux users can just use whatever text editor their distro cam with.
Windows users can use pretty much anything but Notepad. I recommend Notepad++. Get it here: https://notepad-plus-plus.org/downloads/.
Step 3: Create a New Minecraft Instance of the chosen version, Install Forge, and test it.
You should normally use the latest recommended version of Forge. MultiMC will have a Gold Star next to this version.
Step 4: Install and test all "Core" and "Hacky" mods.
- Identify any Forge Core Mods, and mods which use AMS Transformers, Registry Overriding, or Substitution Aliases (This includes Redstone++). Basically mods that change things. These are by far, the most likely mods to cause conflicts. Install them first, one at a time, and test run each one for issues. Try to keep the number of these to a minimum, and make sure your game runs stable before continuing. In some cases you can edit the configs and disable the conflicting feature, but sometimes the conflict is as the heart of those mods, and one will need to be removed. See Step 7 for editing configs.
Step 5: Install World Gen Mods
Identify and install, one at a time, any mod that adds to the world generation. These mod may conflict with each other (not so mush crashes, but like screwy world gen. You can usually fix this by tweaking their configs. (See Step 7)). Also install an X-Ray Hack (Mod or texture pack) and check that your ores and dungeons are generating the way you want them to, then remove said X-Ray Hack.
Step 6: Install all other mods
Finally, you can install the rest of your mods, one at a time, and test each one. Be mindful of the core and hacky mods you installed before, specifically checking for things that they might be breaking.
If you are installing a large number of mods, you will likely need to increase the Memory Allocation. Click edit instance -> Settings and set the minimum and maximum memory. The Maximum, is the highest amount of RAM Java will allow Minecraft to have, before forcing the Garbage Collector/Crashing the Game. The Minimum, tells Java's garbage collector to be really lazy until the game's memory exceeds this amount. If it's too low, Java will be garbage collecting to often, which will cause the game to lag often. If it's too close to the Maximum, the Garbage Collector will be too lazy and then lag hard. Usually, provided you have at least 8GB RAM, a Min of 2048MB, and a Max or 4096MB, should be excellent for even the largest packs (200+ mods). If you have a smaller pack and want to allow for 4GB computers, a Min of 1024MB, and a Max of 2048MB should work just fine.
Step 7: Edit you configs
To edit your config files, simple click "View Config Folder", and right-click and edit the file you want with you UTF-8 complaint text editor. Make whatever changes you want and save.
Step 8: Test you Pack
Test everything one more time, make sure it all stable and the way you want it. Then, play and enjoy.