It's simpler than it sounds - if you've got a pre-defined job in a file like that, you basically go:
...and it'll go off and run. The results can be a bit hard on the eyes if you're not used to them, but you can make things simpler by deleting the rand-read and rand-write stanzas from the script since you're only testing sequential throughput at the moment.
Likely you'll want to tweak the values inside - for example the mount point of the drive/array and the block size (the one I linked to uses 4k blocks which are where SSDs shine but that might not max out the sequential throughput, so perhaps change it to 128k or even 1M blocks.
fio's a very powerful - and necessarily complex - tool, but like a Swiss army knife it's pretty easy to figure out what at least some of the attachments do
I'm pretty sure fio always needs a test file sitting on the filesystem (I've only ever used it as such); the fio script I linked to, unedited, would try and create a 10GB file called ssd.test.file in the directory /mount-point-of-ssd. Obviously you might want to pick a 120GB file called cuudliers_fio.test at /path/to/my_raid_array.
Up one directory is a dizzying array of different test scripts which you can have a look through for other ideas, but the one I linked to is a good starter for ten.