calculate time spent working but ignore a set break period

Hello, I made a account just to ask this question.

I want to do a sort of work table showing the time I started and the time I finished with a 30 min break in the middle for example, which then calculates the total time worked next to it taking away break time, I'm a novice.

Here is a example.

This is in time;

Start Lunch End Time spent working (hours)
09:30 13:00 15:00 Time goes here.