How do I set the t keys on my keyboard?

I use the keyboard on the ps4 for fortnite

Normally, such keyboards have a driver which you can install on the PC where you can set these buttons. How exactly does that work with a console, I can't answer you. Most of the time, these settings are saved on the keyboard after being made to a pc in the driver.

The keyboard is plug and play no drivers that have been installed have it also connected to PC (Windows 10)

Every keyboard and mouse should now support plug and play, but many have a driver 😅

Found the driver after 20 minutes point and click adventure😅

(I'm not sure if that works but try it) You have to go to Settings in Fortnite. There you go to the tab "Button Settings". There you can set a button for all actions in Fortnite. There you choose what you want to use the T-keys for and that's it.