Go to https://po.sikkasoft.com and enter your Optimizer Classic credential information, then click Sign On.
Once you're on the Home page, hover your mouse on the Sikka logo in the upper-left corner and click on it.
Another window will pop up. Verify that you have the correct practice. Click Choose File, locate your saved logo from your documents, and click Upload.
Please note that you will need to log out of your account, then log back in to see your new logo.