Bleeding the master cylinder

[jocaan]

Recently bought this 94 Suburban so do not know history.
While trying to bleed the brakes I allowed the forward part of the master cylinder to drain out. So now I need to bleed the master cylinder.
Could someone give me the steps I need to follow in order to bleed the master cylinder?
Before and after the forward master cylinder drained low the bleeding was not going well-getting very little fluid when opening up the bleeder screw.
If I should bleed from the two fittings on the master cylinder does it matter if I bleed from the forward one or the second one nearest the firewall first?
I installed two wheel cylinders before attempting to bleed.
TIA, Frank C.