Too obvious but does the wireless mouse not need to have a dongle plugged into a USB port (if you find them)? On an expensive Dell I found the dongle inside the wireless mouse, wrongly thinking that I did not need one. Also the mouse has a small on/off switch on the base. Also my Dell only has Thunderbolt USB - C's so I bought an adapter from Amazon that has 2 USB, 1 HDMI and a SD slot. I leave others to comment further.