Enter to [Template > Media library]

Upload image by opening folders or drag-and-drop

Tripple-click on URL, Right-click and Copy
*NOT DRAG

Enter to IAM Studio

Enter to [profile→custom font]

Enter to font name and paste font file URL (You can check font you set in editor)
Click plus button
Finished!
Enter to IAM Studiofont name and paste font file URL

Enter to [Profile → CUSTOM FONT]

Click [Add Custom Font]

Enter to font name and paste font file URL and Click +Button (You can check font you set in editor)

Finished!

You can check the custom font you set in editor