Install texture mods via ALOT installer.Install content mods via ME3Tweaks Mods manager (see individual mod guides below).Mods must be installed in this exact order: Not following the instructions precisely can just as easily break the game, which can happen anytime in a playthrough. If a mod author says to read the docs, it means you really, really should.
Modding Mass Effect is special in that it's not drag and drop modding like most games these days. Download ALOT into a separate folder, and use it to choose all the texture packs you wish to use.Download the content mods you wish to use, into a content mods folder (when available, I recommend using the torrents).Start up Mod Manager, and do a game backup.Download the modding tools (Mod Manager + ALOT).Install the game and all applicable DLC (all official DLC + multiplayer DLC recommended).The initial process can take a long time - come prepared with a good book while you wait :) The only way is to start over entirely, using a previous backup of the vanilla game (which can be done with the mods manager). Once the texture mods have been installed via ALOT, there is no going back to modify something, or add additional mods. Modding Mass Effect games can be considered a one-time process. DLCs are simply loose files bundled together, which makes them easier to install. Some mods come as loose files that have to be copied into the game folders, and others come as DLCs.