@Beatrice
So, the automated onboarding system I mentioned should have given you a button at some point telling you to post an introduction. If you want to find some people to talk to right away, the best way to do that is to Make a post with the hashtag "introduction", talking about yourself and what you want to talk about, with hashtags for all of those things. You can also follow hashtags, which is the best way to quickly find things.
So like, if I were you, I would follow #finance and #economics, and make an introduction post that uses them. (This post is set as "unlisted", the little unlocked icon below, meaning it won't come up for those hashtags even though I put them in, so make sure your introduction is set as public.)
I should also know that there are a couple major economists whose primary presence is mastodon, like Robert Reich, so you may want to follow them too.