I use a laptop all of the time, but both the ones I currently have are too heavy to put on my knees. So here (we're at the caravan) I have whichever I'm using (long story!) set up on a tray beside me on the bed. Bit of space around the edges is useful for pens, pencils, dibber for my phone, spare pencil leads (in little container) for propelling pencil and Pretend Ciggie. Though most of the time these days here I'm so bloody stressed that I'm smoking a lot of Proper Ciggies!

(Long stories over that too - blame the so-called "Couriers" Evri.


) Remind me to give you a long rant about Evri!
Anyway, to get back on topic... I have a separate keyboard and mouse that connects wirelessly to a little diddle that fits in one of the plug holes on computer. You can see it between the two blue lights on edge of computer and the pens.
(The Green Owl Badge is Duo who is in charge of Duolingo. I'm learning French and Maths, after learning Welsh and Latin. I tried Spanish (some of Grandkids are learning that), but I didn't like it. My next plan, if I ever finish the French course, is to try Italian.)
I don't bother with a mouse mat, just use the quilt cover.
I tried to put a link to it on amazon, but it gives a page linked to my account, so you'll have to search for it on amazon yourself if you're interested:
Logitech MK295 Silent Wireless Mouse & Keyboard Combo with SilentTouch Technology, Full Numpad, Advanced Optical Tracking, Lag-Free Wireless, 90% Less Noise, QWERTY UK English Layout - Black
(It comes in White too, if you wanna colour co-ordinate!
)
At home I've got an over the bed table from IKEA that goes right across my king size bed, so laptop and a load of junk goes on that. Unfortunately IKEA don't sell them any more. Not that I've looked at their website recently.