There is nothing to do with the clutch master with the bleeding process. no bleed nipples on it.
The fluid had to go some where. have you looked for a leak? did you look under the floor mat? No since bleeding the system if there is a leak, you will be right back to square one.
Did you look at the Video I posted? he uses a pump oil can in the demo. some have used it with success.
As Steve said to do with pumping the peddle and clamps on the hose to the nipples. you want an air tight seal. you don`t want to reintroduce air around the nipple threads.
One thing to think about. If the brake system and or the clutch system hasn`t been flushed out in many years, you will be just loosening up gunk and what ever and just circulating it through the clutch lines and the line to the R/F caliper.
Also if there isn`s a rubber cap on the bleed nipples. there will most likely be dirt and grit in the hole to get pushed into the system. make sure they are clean.
There is not a lot of room between the tunnel and the Slave cyl to work. can be a pita to work on. once you get through the frustrations of clutch bleeding, you will get a nice certificate from the Forum, "I Survived Clutch Bleeding 101".
Charlie