Cliffe, welcome to the Zorin Forum.
If you could, please first run
sudo apt clean
and
sudo apt autoremove
and declutter some crowded hard drive space.
Next, to expand a partition, open Gparted on your system.
You can use the Partition ... resize/ move function to resize or expand a partition. It looks like you have plenty of freespace available that you can expand into.
Usually your Root can be around 50 gigs or so and I personally let my Home folder hog the rest, although I admit I rarely let my home folder grow enough to occupy more than twenty gigs.
For a detailed walkthrough with images, please see the Gparted help guide:
https://gparted.org/display-doc.php%3Fname%3Dmoving-space-between-partitions