For stacks that you use more frequently, you can mark them as Favourite. Just tap on the little star icon so it shows ‘filled’ as in the image below. To remove the stack from the favourites, tap on the star icon again.
To see all your favourite stacks, click on the icon in the top menu bar and then select ‘My Favourites’ from the drop-down menu.
To remove a favourite stack in the My Favourites view (see below), tap on the little star under the banner with the stack name and to the right.