If you have an FAC then you join the NRA.
Having joined, you ask for an SCC assessment for the categories you want/need e.g.
Scoped Rifle
Iron Sighted Rifle
Gallery Rifle
HME
Target Shotgun
They will book you in, you attend, take a multiple choice safety exam (they'll give you the material in advance, if needed), then you go out to the range and do some shooting under observation to make sure you are A, safe and B, can hit the target.
Once that is done, the office will normally issue the SCC there and then. If you want more than one category, try and arrange all on the same day.
Once you have the SCC you can book Bisley ranges whenever you like as an individual or as part of a group, mark your own, pay for a marker or use the electronics. If part of a group then all of you will need an SCC.
It sounds complicated, but it is very simple. I have added HME and Gallery to my SCC on this basis and both times it was a very simple process.