Since you replace the master cylinder it must be bench-bled which basically you will fill up the reservoir with fluid, connect hoses to each outlet and either have them directed straight back into the reservoir submersed in fluid or into another container with brake fluid, then you slow push in the plunger until no air comes out and it feels good and solid. This can be done with it mounted in the car also but you still use the same proceedure. After you have done this then you can bleed everything else normally.
