I got you, friend Here's how you can save and load outfits:
Set up your avatar the way you like it, including both the body/face and clothing. Then navigate to the Saved Outfits tab at the top. From there, you can select the "Save" option along the side. If this is the first time you've used this feature, the slots on the right will have white (empty) thumbnails.
Select one of the empty slots and click the Save button. (I'm doing this on PC but it works more or less the same on console.) You will be able to give the outfit a name to help you remember what's in it. You can also save over an existing outfit to replace it, if you like.
Next time when you want to switch your avatar back to this saved version, just navigate to the Saved Outfits tab again.
All of your saved slots will appear on the right hand side. Choose the one you want, and select it to swap your outfit.
Ta-da! You can also delete saved outfits from here if you want to free up the save slot.
Hopefully that helps!