It says on your profile you are from Romania.
Use this to find the prayer times in your city.
Let's assume you are in
Brăila
At 12:19 the time for the Dhur prayer starts.
You can pray after 12:19 regardless of if the adhaan has taken place or not.
It is best to pray the prayer at its earliest time.
So you should pray as close to 12:19 as possible.
Once it is 12:19, go do Wuduu and pray.
If you go over by 30 minutes no problem.
Just be careful about maghrib.
The maghrib time on the chart is 6:07. This means you can pray once the clock strikes 6:07.
Do Wuduu at that time and begin to pray.
Check the chart daily as the prayer times move.
The other thing you can do is that when the adhaan takes place, do Wuduu, and pray.
If you go over by 15-20 minutes there is no problem because the adhaan is given close to the beginning of the time of prayer.
So you have a good gap in which you can pray before the time of the prayer expires.