Scrollbar text boxes Answered

I have just started making a few Arduino Instructables and am wondering how I can put the scrollbar text boxes like at Step 15: Program of this Intructable https://www.instructables.com/id/Arduino-Countdown-Timer/?ALLSTEPS
I do not have Pro membership. Also is there any way to post formatted Arduino code within the Instructables. Hopefully someone might be able to help me with these questions, thanks Pedro.