User`s guide

If the cursor turns to two vertical lines with left and right arrows, it is pointed at the
partition border and you can drag it to enlarge or reduce the partition’s size. If the cursor
turns to four arrows, it is pointed at the partition, so you can move it to the left or right (if
there's unallocated space near it).
Having provided the new location and size, click Next. You will be taken two steps back
to the partition layout. You might have to perform some more resizing and relocation
before you get the layout you need.