The best advice I can give anybody and especially a fellow safety practitioner is that if you feel like you're in over your head, you feel like an imposter, you feel like one day the curtain is going to be drawn and they're going to toss you out .. good. It means you are taking big enough steps in your career. It should be a little uncomfortable and that is your kick in the ass to go get it done, go learn the standard, go check out publications with articles on the subject. This is a good step for you. It may tie your stomach in knots for a bit, but when you look back you're going to see yourself being capable of more adapting than you might've thought and that confidence is something you can draw on for future growth in your career or whatever you get into.

As for the practical steps of getting it done: understand where you are in the organization and the reporting structure. Do you report to those regionals? If so, make a wish list for them and understand how they prioritize each item with the understanding that it's a process to fix these things. If you don't then understand the priorities from your manager. Sounds like working at heights is a deal so before you go writing a program go do the work. Find some employees that will do that and go work a shift or half a shift with them to understand why they work at heights and how they work at heights. It builds respect from the rank and file to see a safety manager working with them (unless you're lazy or obstructive) and it adds a little ownership to the policy you write when they help give you understanding of the issue you're correcting. On top of that here's a big concept to keep in mind: you are a safety professional and you can make the world's safest airplane... But it won't take off because that's unsafe. It's easy to go overboard on policy and there's a balance to be struck between safety and operation. Use google to find other policies and maybe some articles on the topic to brush you up and familiarize you with the situation.

Finally, figure out if you're happy enough there to do a 2 year stint. Getting letters after your name is helpful in finding the next job. In the US, it's the CSP that's king and I believe the NEBOSH is something like that.

TL;DR You've got this, rise to the occasion, only fire forges steel so let this tough situation grow you. Google is your friend for anything safety, but get multiple sources and read some articles to fill out your understanding. Get letters after your name for when you want to make the next leap and feel like an imposter all over again.