I’m installing a 4n1 hobbywing 60amp ESC and directions are a bit vague.
  
   
  Setting throttle range is mentioned if using single ESC in the directions and that’s about it.
  
 Doesn’t mention how to flash or update if needed.
 
     I looked for a build thread using this stack combo and nothing so far.

  I think I just solder up pigtail,capacitor,motor wires and join it to the FC with plug wires.
   
 I just don’t want to solder everything up and find out later I needed to flash or update it before attaching wires.
    I see a servo plug with wires and I’m assuming it’s for calibration and or flashing.

  My frame is built and it’s ready for ESC and FC.
  To get started with installing 4n1 can I start soldering up motor wires and then flash or calibrate if needed later in the build?

You would flash it through the BL heli 32 suite, using the pass through function which can only be done connected to the FC. Unlikely you will have to do anything, go ahead and wire it up.