When you're planning an activity, you have the option to make it a recurring task.
To set one up is simple! You simply select Plan Activity > Repeat > then select at which interval you would like it to repeat from the menu
After creating a repeating task, the future dated tasks will not appear in your planned activities until the current task has been marked as 'done' or 'won't do'.
If you would like the planned activity to stop repeating after a while, just select "Don't repeat" on the most recently assigned task.