[SOLVED] No touchpad found

I have just installed KDE Plasma, and have no touchpad. Settings - Touchpad says, “No touchpad found” in a red box. At the moment, I have attached a USB mouse. How can I get the touchpad working please?

For information, my laptop is a new Acer Swift 3 (AMD Ryzen 5 4500U Radeon Graphics).

Thanks in advance.

UPDATE: Following a system reboot touchpad functionality appears OK.

not only in linux but in windows also it does not install