To see all your tasks, requests and group tasks for a workflow, click Workflow in the sidebar menu, and then click a workflow.
My tasks shows the workflow tasks assigned to you and that you need to perform.
My requests shows the workflow requests you have created.
Group tasks shows the workflow tasks from created requests that are available to you to pick up and perform. The tasks that are available to you to perform are tasks relating to model packages you have been invited to. You do not need to have access to the site the request is created in in order to be able to perform the task. However, in order to be able to see what the task is about (the view or element for example), you need to have access to the site.
Clicking a request opens the subject of the request, and the work previously done on the request. If the request is assigned to you, you can perform the next task in the request.
Overview of tasks and requests of the "Change request" workflow