You don't. and you never will.
2008 (March) - Apple® releases the first iPhone, using iOS®. Steve Jobs is insistent and adamant that iOS® is NOT compatible with Flash® and NEVER WILL BE. Jobs' reasoning is that playing Flash® content is processor consumptive and it drains batteries, thus shortening the life of them in mobile devices. In six years, that hasn't changed. Not for the iPhone®, iPad® or iPod® Touch™. It never will change and there never will be a Flash Player® for iOS®.
Apple recommends SkyFire (https://itunes.apple.com/us/app/skyfire-web-browser-for-ipad/id409153623?mt=8) in the App Store.