For (1) - if you mean app, you can create a new one by heading to your Retool homepage (if you’re in your onboarding app - click the 3 dots at the top left and then “home”) and clicking “create new” - there are a few different ways to create apps, from scratch, via a template, cloning another app, etc.
For (2) - you can’t exactly open a Google Sheet directly in Retool - you need to work with it programatically. A typical use case is querying the sheet and displaying the results in a Retool table component - we have a walkthrough example in our docs here.
This does help! I think I’m trying to do things a bit more programmatically than it seems I am able to do. I’ll give an example: I’m trying to create a drop down whose inputs are automatically generated from the text in a field. How would I do that?
Another possible example:
I want to program a button to list out all values from the first column whose column three = [some value]. Is that possible to do?
Once you get the hang of referencing component properties things should fall in place.