It’s not very intuitive if you ask me.
Go into Options > Controls. If you have the stick installed in windows you will see it listed across the top of the Controls screen.
Down the left hand side select ALL in the filter to show all available controls.
Search for what you want, lets say “Elevator”
You will then see what elevator controls you can bind or assign to the stick.
For the Sidewinder, click in the grey box to the right of “Elevator Axis”, which will bring up an Elevator Axis sub-screen
Drop down the Select an input box, and scroll to “Joystick L-Axis Y” and select it.
Next click Validate and this should drop you back a level and you will see the Elevator axis is assigned. You can check it works here by moving the stick and seeing the response on the screen.
Then, rinse and repeat for everything else. Don’t forget to save!
You can create multiple profiles too, but I haven’t ventures that far yet.