Let me define the features for the app in detail before starting the initial build

I want the options to add more detail about features the app should have before starting the initial build. Right now it forces me to start building right away even if I dont want to. There should be an option to add more details before starting the build.

Especially if I'm being mindful of credit spend, I dont want to spend credits on a loosely defined version of an app that I then have to iterate on to get it where I want it.