My first app requires a timer and a dynamic text box - Where to start

Hello

I am starting the tearning curve to writing an app for my galaxy phone.

Me and my friens play a lot of “Texas Hold-Em” and, for those that do not play poker, the rules are that the blinds (minimum bet) doubles after so many minutes. We have played for 30 years and we are continually forgeting how much the blinds go up by, especially after a few beers and 4 hours of play, so I opted to write an app for my phone that controls the timer and lets us know the correct blind.

I have done the hello Android tutorial but I am having trouble finding a tutorial that will allow me to manipulate the clock. Any links to a tutorial of a clue where to start would be appreciated.ode