How to lock my touchpad/mousepad on lenovo thinkpad laptop?

I like using a mouse more than a pad
but when I'm writing something and skim over the mousepad it mixes my sentences up.
I never use the mousepad

so what can I do to lock the mousepad?
I went under devices for settings on my laptop for the mouse and there's nothing at all about disabling the mousepad

Added (1). touchpad does not open up only the physical mouse I use can be disabled

1. Click Start.

You can also disable your touchpad in the Device Manager.
2. Type device manager into the Search box. Click the device manager result, and the Device Manager window will pop up.

3. Expand Mice and other pointing devices.

4. Right-click the touchpad's entry. In the menu that pops up, click Disable.

5. Confirm your choice in the pop-up window.

Check your function keys; they are labelled F1 to F12 and most of them have secondary functions you can activate by holding down the Fn key before pressing them. Disabling the touchpad should be among them.