1. open up the bleeder valve on the clutch slave cylinder ( just crack it open, don't remove it all off)
2. attach a clear hose to the valve with some sort of container to catch the fluid, I use a water bottle. open up the master cylinder.
3. have one of your friends sit in the car and pump the clutch pedal, at this point it seems like he or she will have to start off by doing it by hand. eventually it will get harder and they will use their foot for the rest of the job.
4. This part is crucial, as they are pumping the pedal you will have to be observant of the master cylinder and the bleeder valve. as they are pumping make sure to keep the fluid above the "min" mark. If it gets below you will end up getting air in the system and will make the process take longer. while checking that, take a look at the bleeder valve and you will notice bubbles being pushed out. keep topping off the master cylinder until you see no more air bubbles coming out of the bleeder valve. you can tell your friend to pause the pumping if you need to add fluid.
5. once you feel the bubbles are gone, make sure to close the bleeder valve.
As far as your clutch slipping issue, it sounds like a slipping clutch.