###Step 1: Download or clone the repo Click here to go to the repo ###Step 2: Import existing modules you want to build off of, or create your own. Before we continue, make sure you open command prompt, so you can enter some commands in.
(tip: you can hold shift and right click where the repo is saved, and left click open command prompt here, it will automatically open command prompt on that directory)
if you didn't navigate to the directory already, then just type
cd "THE REPO DIRECTORY"
example:
cd "C:\Repositories\TerasologyRepo"

To import a module, use
gradlew fetchModule[MODULENAME]

Here are some examples:
gradlew fetchModuleSample
gradlew fetchModuleNguiExample
gradlew fetchModuleQuest

To create your own module:
type the command
gradlew createModule[MODULENAME]

example:
gradlew createModuleMyFirstModule
this will create the module, and name it "MyFirstModule"

###Step 3: Build your workspace for your preferred IDE Eclipse:
gradlew eclipse
Intellij
gradlew idea

If you import any modules in the future, make sure to call this command again, to re-build the project files to be able to import it into your workspace

###Step 4: Import your project to your workspace Eclipse
First, rightclick your package explorer, and leftclick on "Import Package"

Second, expand "General" and leftclick "Existing projects into workspace"

Finally, import the repository path. Just copy the repository directory, and paste it into the "Select root directory" text area

And done! now you can start making your mod!