Reading Tournament Game Clock

Hi Friends,

I am a Novice in chess. I wanted to know how do we read the below. I am taking my 5 year old kid to a tournment, but the tournment says the below. Can anybody help me understand how to read these or give me a link where I can find how to read it.

4 Round RR, g/25+3sec

Thanks

https://en.wikipedia.org/wiki/Round-robin_tournament

Not sure about the 25 minutes+3, but it's either delay (there are three seconds after starting the clock before time starts), or increment (3 seconds is added to your time each time you move).  Think it depends where you live...

Thank You. The Wikipedia seems very complicated for me to understand the math. But the second post of yours gives me some idea. So for every 3 seconds are we going to complete 1 minute from the start of the game ?