Vysous

Dear all, I have an issue with the auto step climb feature. I programmed the step climbs in the FMC - I could see estimated times and altitudes, as well as S/C in the flight plan. Question - what is the altitude I set on the MCP? I assumed that I always set the current cruise altitude, and when step climb waypoint is reached, the plane will automatically change it to the new cruise level. Is that correct? Or do I have to enter the altitude "after" step climb? The reason I ask: When the plane was supposed to step climb, it simply told me "STEP DELETED" and did not do so. I ran out of fuel during my overnight longhaul and crashed.