How do you use the F3 commands in Minecraft?

I recently started new with Minecraft on the PC (previously had the Pocket Edition) and I've made smart on the Internet first. If you press F3 you should come to the debug screen. I'm not so good with PCs yet and the sound is louder with me.

When the sound gets louder, you have double-use on the keyboard. The F-keys then have 2 functions. Once so pressed and once with Fn key to switch to the 2nd function.

After your description there should be an FN key press this together with F3

Do you have the Minecraft Windows 10 Edition, from the Microsoft (Windows) Store?

Thank you, that worked!

No, the Java version.