You can perform two quick actions for the epics listed on the left:
Link an issue
View epic details
There are also several quick actions you can perform for each issue by simply clicking on the three dots at the end of the row:
Link: create a link to another issue
Change summary: Change issue summary
Time tracking: Input work log
Assignee: Assign the issue to a user
Transitions: Change the status of the issue
Priority: Change the priority of the issue