Trying to Use /api/dataset Endpoint to Query Table

I'm trying to query a table I have in Metabase using the api/dataset endpoint but it's requiring a database number and I'm not sure what that is supposed to represent or where to find it since my databases only have string names (I tried just using one as most of the examples I've found just did that but then I get the error "The instance you tried to reach does not exist. Please check the domain in the address bar, or create a new instance in the store.").

Anyone know where to find that number or what this error could mean? Thanks!

go to settings->admin->databases and click on them, you'll see the database ID on the URL