You pick up on the arm with the blade on it. Then you wiggle it off the spline.....if it doesn't have a obvious nut or bolt on the end of the shaft. They are a Bitch! But there are special tools that make it easier.
The one is hard to find....Made by Anco....It's a2 prong forked arm tool.....The wiper arm has to come off evenly.
But there is another tool...IF it has a bolt in the middle.....It's a mini 2 jaw puller.....also used to pull batt cables off automotive top post style batteries.
Not exactly where wiper arms park....and make sure motor has parked ...Then reinstall arms correctly.....Otherwise you will be fighting to get them off again and probelly skinned something up.