@blueicetwice hello, I'm assuming you are on solus and judging by partition sizes is an installation with manual partitioning.
Explaining to my understanding, sda is your hardware drive (ssd or hdd).
sda1, sda2,sda3,sda4 correspond to partitions inside your sda drive.
from here:
sda1 is used for storing the EFI boot partition, needed to boot your operating system. It's 1G in size, solus makes it around 512MB (minimum required) but I've read in the forum that it was 1G, so, I assume there is not problem in it.
That free space of 4.5G, I don't know what is doing there, probably wont hurt you.
sda2 and sda4 could be there to store the root partition / (for the operating system) and home partition /home were user data is stored (desktop, documents, downloads, etc...) for example /home/user/downloads.
sda3 is 1M in size, don't know what it is for but I wouldn't delete it. probably won't hurt you ether.
The box bellow just brings more info about each partition.
I hope it helps.
