The ALEKS2Canvas Gradebook add-on can be installed from the Google Workspace Marketplace. The link below will take you to the installation page.
To start using ALEKS2Canvas Gradebook, in Google Drive, create a folder that will be solely for your ALEKS2Canvas Gradebook spreadsheet. Inside the folder, create a new spreadsheet. The title of the spreadsheet and folder do not matter.
After creating the new spreadsheet, open it, and find the Extensions menu on top. Select Extensions > ALEKS2Canvas Gradebook > Enable. This gives ALEKS2Canvas Gradebook permission to operate in the spreadsheet going forward.
Navigate to Extensions > ALEKS2Canvas Gradebook > Setup > Launch Setup
The setup sidebar will guide you through the setup process for ALEKS2Canvas Gradebook. Each step should be completed and in order to ensure the spreadsheet is setup correctly.