Have no worries mate!
You simply edit that file e.g. with command
sudo nano /etc/fstsb
Sudo gives you the required privileges to edit this file.
Nano is a relatively easy to use editor.
Each partition you want to mount needs a line in the file.
Look at the existing lines how they are constructed.
But before editing you need some info about the partitions, e.g. command
lsblk -fm
Then the mount point: it is a directory where a partition will be attached.
You create a directory for each partition, e.g.
sudo mkdir -p /mounts/p1
You can pick the directory names quite freely.
Now you use this info when editing the file. Use the correct UUIDs from lsblk and the created mount points.
And read man fstab again about the parameters.
But now I have to go, hopefully others can help further if needed. Will be back tomorrow.