Filling it is a good idea, in fact a very good idea.
From what it sounds like, it is the clutch pot, and yes filling it is a good idea. If you have totally run it out of fluid, it will need to be bled to get the air bubbles out, which isnt too hard, just time consuming. you need two people to do it. One to pump the clutch, and one to bleed the system.
Just filling it up wont fix anything. The air bubbles are stiil there.

If you dont know how to bleed the clutch or dont know anyone to do it for you, you can either pay a mechanic to do it, or dont use the clutch at all. I generllay dont use the clutch in my datto. It saves a bit of wear and tear on the clutch as long as you do it right.