It is fairly straight forward. Are you comfortable opening up your carb. It could be done with the carb on the car, but I would suggest taking it off. There are a lot of detailed instructions around on how to dissasemble a QJET, but I will outline what you need to do -- this is from memory, so it can only be used as an indicator if you want to try it.
1) Remove the pressed pin that holds the accelerator pump arm and remove the arm
2)Remove the screws from the top of the carb ( There are like 12 of them)
3) disconnect the choke rod from the butterflies. This is the most fiddly part, there is a little connector that connects the rods, fiddly to get it apart, more fiddly to put it back together. But very do-able
4) Lift the top part of the carb off. the accelerator pump will probably come with it, along with the silver primary solenoid piston (not sure of the name of the silver part that pushes down the primary rods)
5) the TPS should then slide out
Replace, assemble in reverse.
There is an adjustment procedure for the TPS. I can send it to you if you would like.