Why doesn't Minecraft Forge work?

If I install forge it works.

Then I have The Forge installer

Then when I download Forge, it works, and I get a message that it has been added to the launcher.

But if I then go into the Minecraft Launcher and go to a new installation and then scroll down to the bottom, forge is simply not there.

Maybe someone knows what I'm doing wrong (I'm using the official website and have already tried several versions of forge and it just doesn't work)

For me it is no different. This site is strange