Check out this video walkthrough:
After installing ReachApp, you’ll find a simple preference panel in the stock Settings app. Bear in mind that the tweak is still very much a work in progress, but there are a few switches in the preferences for you to configure the workings of the tweak to your liking.
To use ReachApp, simply open the two apps that you’d like to use together back to back. For example, I can open the Safari app, then open the YouTube app immediately afterwards. After tapping on the Touch ID sensor on my iPhone 6 Plus, which is normally used to invoke standard Reachability, ReachApp is invoked. This will take the current app being displayed, and shift it down to reveal the last app that you were using in the background. You’ll then see a small grey bar separating the two apps, and you can slide this bar up and down to reveal more of each respective app.
At this juncture, there are some bugs and some issues with things like landscape mode. But developer Elijah Frederickson isn’t new to developing jailbreak tweaks. In fact, he has some pretty ambitious projects under his belt already.
You know there is still no ETA for the public release of the tweak as it is so difficult to develop a tweak like this to open two apps at the same time.. However, we will keep you updated. Stay tuned..