How to disable the touchpad on my Dell?

I am extremely frustrated with my Dell laptop.

Amongst other things that I hate about it, I can't disable the mouse on the keyboard (the touchpad). My other laptops had a button and you just turn it off and this one doesn't. I have wasted so much time trying to find out how to do that. The hot key combination Fn + F3 doesn't work. I read about some drivers need to be installed or uninstalled but couldn't do that either because I am not that advanced.

Please help me - I need just a simple explanation how to do that, that doesn't require me having an IT Bachelor's Degree!

Thank you!