Start by adding a folder for your team using Brand and Assets > Add Asset Folder
Click Add New Folder then add your Folder name and an optional image.
Then head to Brand and Assets > Asset Upload and Edit
Select the required folder from the dropdown
Select your option:
Multiple Asset Upload is best for uploading a whole team, or multiple products in one action
Single Asset Upload is best for uploading single players one at a time.
You can upload up to 50 images at a time.
Then click Add New Asset and fill in each section
You can then edit and delete assets at any time.