Create a Course or use an existing course.
Make sure you have at least one module and published assignment.
Select the Admin tab and click on the blue Edit Details button at the bottom.
Select the ENABLE LTI option.
Click on your user name in the bottom left of your dashboard
Select your Organization
Click on the LTI Integrations tab to bring up the following settings.
From the course homepage, select the Edit Courses tab.
Under Site Resources, select External Learning Tools.
Click the New Link button at the top of the page.
Paste the information below in the URL field (1).
Under the Key/Secret heading, select "Sign messages with key/secret with" and "Link key/secret."
Copy the LTI Consumer information from Codio into (2).
Copy the LTI Secret information from Codio into (3).
Fill in the Security fields as depicted in (4) below.
In D2L connect your modules to Codio assignments:
Select the Content tab from the top of the page.
Add a module to your D2L course.
Select Add Existing Activities (1) -> External Learning Tools (2)
From the list of available LTI links, select the Codio tool you created earlier.
Click on the Codio link to bring up all the Codio courses for which you have enabled LTI.
Select the Codio assignment you want to connect.
Refresh your page to view the rendered connection. You will see the Teacher view of the course with the connected assignment selected. Students will see the assignment opened in student mode.