Dear Jana,
I've recently been improving the BIG STEM Communicators Network website content and we have some pages on how to get started, training courses, a list of science festivals and centres etc. It might be worth checking out www.big.uk.com (go to Jobs & Resources section). I'd also be interested in hearing from you any other advice or tips youg et that we could add to our current information to help others in your situation!
Best wishes,
Lucy Moorcraft