Words inside the IDE
Tap one. You will meet them when Stage 5 opens. Knowing the names now is enough.
Later · pick one IDE
A full IDE on the phone.
IDE means Integrated Development Environment: one app where you write code, find mistakes, and turn that code into a real Android app you can install. Code on the Go can do that without a laptop, even offline after setup. It needs lots of storage and RAM. Most modern phones want the 64-bit version. Android 9 or newer.
Official doors only
appdevforall.org/code-on-the-go
GitHub: CodeOnTheGo
Uses Kotlin and Java. Kotlin is the one Google pushes now.
Gate
If opening Termux still makes you nervous, stay on Stage 3. Do not install both IDEs on a phone that is already full.
Next step
Pick one builder later. Not both on a full phone.