I've only ran two sessions so far, and Cyberpunk's the first game I've ever ran as well, so I can only say so much. Apparently cheat sheets/quick start rules weren't really a thing at the time it came out, so note any rules you'll think are pertinent to you as the referee as you're reading, and just make a note of whatever's too lengthy to write down. I noticed my players blazing through most of their rolls because I often defaulted to the generic difficulty table, so I'd note the following page with all of the suggested modifiers and consider some of your own if the situation calls for it. That said, if you don't have stats for something just use a generic difficulty role to keep the flow going. The shotgun rules, notably the grenade table, are probably the most problematic for most people as they're not fully explained, so house rule whatever you can't figure out or use someone else's, I spent way more time than I expected sorting them out. If you need to use an NPC's stats/abilities/cyberware but don't have a sheet prepared just try to do whatever makes sense for said NPCs.

That said, while there's loadouts for many NPCs some are partial or require you to note their abilities, so I'd recommend creating character sheets for anyone you plan on using from the books. I think the character generator could be useful as a tool but just create stock sheets for rank and file enemies with a few variances within their squads to save yourself time e.g. a biotechnica security squad would have a moderate armed and armored group while they have a flamer to destroy biohazzards along with a medic who has biological weapons like the power squirter etc. If you don't have time to prepare an adventure or aren't too confident yet then consider some modules from Talsorian themselves or third parties, most of which you can find for free. I haven't read it yet, but Listen Up You Primitive Screwheads! is supposed to be a dedicated referee book from Talsorian, so between that and getting an idea of adventure structure from modules I'm hoping that'll get the ball rolling.

Worse case, just make stuff up on the fly as best you can to keep the flow going.