Beginner: Boxing Timer

Hi, im new here. I have no experience with C++ programming. I want to Build a Boxing Round Timer with an Arduino Uno Board. The Timer should have 3min Timer + 1 min pause, then 2min Timer + 1 min Pause and a 1 min Timer with a 1 min pause. The selection of the minutes would go over a switch with 3 states. the output should be a Green Led blinking 1/1 second and in the last 10 sec of a round 2 times in a second. The Red LED should is for the 1 min Pause and should also blink 1/1 and the last 10 sec 2/1. At the end of the Round and at the end of the Pause should be a piezzo peepser powered.

I have Trouble in starting the whole sketch, maybe someone has an Idea??

Sure, try the Stopwatch in the Playground. Add some button reading.
There have been several posts recently for driving LED displays to show time counting down also.
Is a very do-able project.