Student or Learner
If you are at a party and you are talking to someone you might informally say "There's going to be main players tonight." meaning that some important peaople are coming over for the party. We may not say "are going to be"?
We do use the contracted form "There's" at the start of a sentence in which we'd use "There are" if we didn't contract.
There's a couple things I have to do before I'm ready to go.
There are a couple things...
But not: There is a couple things...
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.