A newbie's first question - how to reference to Xano user?

Hi,

I am a bubbler, who finally decided to use Xano for my Bubble app's backend, and just starting to learn and build my Xano backend.

My first work to sign up a new user succeeded. A great progress. But from there, I am facing a challenge.

I have tables of user and restaurant.

On a signup (click SIGNUP button), this new user account is created, then a new restaurant is created (user = this new user). I also need to connect this new restaurant back to the user.

In Bubble's workflow, (1) Sign the user up (2) Create a new restaurant (user = this user), then (3) I need to Make change to the new user to add new restaurant into the user's restaurant field.

Here, I am having trouble with regard to how to call the user.

Could anyone help with this?

Thanks.