Congrats on the job! Once you get a foot into the industry you can only progress. You will make contact with people in yards, you will get to know them.
If you are looking for the admin side of the industry you have plenty of options within the BHA/Weatherys. They are always advertising positions to work in racing operations in the BHA. They also offer racing secretary courses. I work in a yard, and I am now very friendly with the people I deal with at the other end of the phone - vets, registrations, transport companies, supply companies.
Otherwise, it is difficult to get the foot in the door at yards themselves. Pick up the phone, but do not ring the trainer direct. The trainer has enough on their plate and will forget about you about 10 seconds after they hang up. Email C.V.s - any reputable yard is online these days with their own websites and it isn't hard to get contact details.
Stop for a minute, open your mind, learn. You may not agree with what I say, I may not agree with what you say but we will both learn something new.