The old shaft has to come out just to get the switch off the dash. And you do that by reaching up under the dash, finding the push button on top of the switch, and pushing it down while pushing in slightly and then pulling the knob and shaft out.
(Yes, you can take the knob off the shaft, but with the shaft still in the switch it isn't easy to get the switch out.)
And you have to remove the instrument bezel to be able to get to the nut that holds the switch in.
But it isn't all that hard. However, if you have big hands it won't be easy to operate that push button. And if you have thin skin you'll likely be bleeding before it is over. So maybe get someone with small hands to help you?
Gary, AKA "Gary fellow":
Profile
Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI