If the items are in your 'To Plan' section you can decide when you want to plan this work item for and move it into 'This Week', 'Next Week', 'Later' or 'Done'.
However, in each bucket, you can filter items in this view to get to the item you need most and plan when you want to work on it by using the drag and drop functionality and placing it into the appropriate bucket.
From the work view, you are able to plan or change your plan for the work items listed.
To do this from the Kanban view, click on the three dots and choose ‘Plan Work’.
If you're using the List Mode, you can do this by going into the 'Planned Week' column and selecting the work item you'd like to edit.
You can then select when you or your team will do the work. This will then be updated in My Week.
From the work item, if you navigate to the detail section and go to the work team, under the Planned Week column, if you click you are able to do the same as the above.
If you have a budget, a task, or are the work assignee, you will have the work in My Week automatically and will be able to do the above for any of the work items you are involved in