It helps to know what Music Creator version you are using.
Generally speaking there are two different approaches you can take.
Approach 1 you view your Music Creator Groove Quantize path settings to discover the demo loops folder location, create a new folder and add your loops to the new folder.
Approach 2 you install your loops wherever you want and then change your Music Creator Groove Quantize path setting to match the location where you stored the new loops.
You access Music Creator path settings by (1) pressing "P" on the computer keyboard > File > Folder Locations > Groove Quantize or (2) Edit > Preferences > File > Folder Locations > Groove Quantize. I've (hopefully) inserted an example screenshot below.