Well..... sound slike it would help to have someone local to help....

but over simplyfied.....

Mixing is using a computer radio and setting it up so when you do one thing.....something else happens....
there are MANY different mixes....

like... you apply flaps so then your system automatically applies a bit of down elevator due to increased lift....

or,,,, you apply rudder to fly a knife edge and the system automatically applies a bit of ailieron and elevator to fight coupling...
those are a couple examples, but there are MANT more....