Anyone know anything about it?

I am very confused on the example try out problems our professor gave us..

for example,

ax = 06AF and the command says

mov ah,3

So does that mean move a 3 into the high order bit of ax? resulting in 36AF.
??

Any advice? I am not asking you guys to do my homework, just help me understand. I know you can't use the mov command when trying to mov from memory to memory.. but is an example of memory a variable?

like what is cs and ds? are those registers?