The clutch fluid receives the same fluid from the brake master cylinder.
Just use normal DOT 4 is fine and brand of your choice.
Basically if you look underneath where the engine oil filter is you will see it.
I would recommend you DO NOT allow the level to go lower than the lower mark.
From experience I would also use a power bleeder for that aspect next time.
As I unfortunately got an airlock and couldn’t get it out without removing everything and starting again.
A right faff and others have also experienced that problem.
Good luck.
PS Have a read of this. 