My son suggested I check the fluid level in my tranny and I am at a loss... I know in auto's there is a dipstick but... I have no idea what to do with my manual.

The reason he said I need to check the level is that my tranny has started to make a growling noise, I asked if it was the throwout bearing and he said to start with the cheapest fix first and make sure there was enough lubricant. So, if I find the level is low what kind of lube do I use and how do I get it in there? Like I stated above - I'm used to automatics so I need a little guidance with the manual.