Go to your course’s Admin Console from the dropdown menu in the top right
Go to the Questions tab
To find specific questions, search for the question text or use the dropdown to only look at questions that match a certain parameter or are in a particular topic
For smaller changes, click the preview button and edit from there
For more substantial changes, click the edit button from the question list or preview popup
Select the desired questions from the checkboxes by the problem number
Click the “Bulk Edit” button at the top of the page
From that page, you can make small changes to individual questions and add a topic/topics to the group as a whole by clicking the “Assign Topic(s) to Questions” button and selecting the relevant ones