UgoCraft 1.7.10 Example
UgoCraft for 1.7.10 is not a mod that is loaded via a modloader like most mods. Instead it is loaded directly from the official Minecraft launcher.
Here are the steps to install UgoCraft for 1.7.10. You can generalize these steps to any other mod that is meant to be installed in the same way.
1. Download the mod from the UgoCraft developer's official website: https://www.maocat.net/?page_id=7482
2. Move the "UgoCraft_Client_MC1.7.10-2.3.0.zip" file to the directory of your choice and unzip the file.
3. Move the extracted folder to your .minecraft directory at ".minecraft\versions\UgoCraft_Client_MC1.7.10-2.3.0"
4. In the official Minecraft Launcher, create a new installation.
5. In the new instance,
5.1. Change the version to "release 1.7.10".
5.2. Click on "MORE OPTIONS".
5.3. Add this JVM argument to the right of all existing JVM arguments in the installation: "-javaagent: <full path starting from root>\.minecraft\versions\UgoCraft_Client_MC1.7.10-2.3.0\UgoCraft_Client.jar"
5.3.1. Example of complete version of above JVM argument: "-javaagent:C:\Users\<your_computer_username>\AppData\Roaming\.minecraft\versions\UgoCraft_Client_MC1.7.10-2.3.0\UgoCraft_Client.jar"
6. Click on "Install" to save the installation.
7. Launch the newly created installation. If you had the "Launch after Install" button checked when doing step 6 then you already did this step.