PicaSim uses the touch inputs as a virtual controller on mobile devices, and the mouse, keyboard and/or joysticks on Windows. By default the planes will be setup to use the controller in the bottom right to control pitch (up/down) and either rudder or elevator (for turning). More advanced planes will also use a controller on the bottom left to control the throttle or flaps, and rudder.
When PicaSim first starts, you will be standing at the top of a hill, facing into the wind, with the glider ready to launch. Press the "play" button (top right) to launch it. Then use the controller to gently turn the glider so that it flies first to the right, then when it's gone a reasonable distance, turn back to fly past the launch point to the left. The glider will stay aloft due to lift from the wind blowing up the slope. Be careful to not let the plane go to high or low, and if you lose orientation, the arrow indicates the wind direction. If in doubt, fly upwind!
You can see an example of this here:
Once you've got the hang of basic flying (it's hard at first - persevere!), try loading some of the other planes or sceneries through the settings menu, or enable the checkbox in the loading screen. Note that the initial scenery has got turbulence disabled to make things a little easier - flying behind the hill or near the ground can really throw the plane around in reality, so the other sceneries represent this.
When flying at flat field sites, the lift comes from thermals - columns of warm, rising air due to the sun - the Genie is a perfect glider for this kind of flying. You need to watch the glider carefully for hints of where the thermals are - the glider will tend to turn away or nose-up as it approaches the thermal core, which is itself turbulent. It will probably help to enable the "zoom view" in the settings. Flatfield sites will enable a bungee (winch) launch, and some gliders have a variometer that indicates the vertical glider motion by beeping. You can also enable additional data to be displayed such as speed, height above launch and flight time. The next video shows some thermal flying:
There are also races where you have to try to fly as fast as possible between a number of checkpoints:
The Android/iOS versions use the touchscreen for inputs. The Windows version lets you use the mouse to move the controllers, but it is a little awkward so you can configure any joystick (gamepad or R/C transmitter via an interface etc), using settings>joystick. The joystick setup is basically the same on Android and Windows:
The Windows version includes all the planes/sceneries that you can inspect and modify (I suggest making a copy rather than editing the originals!). For more information or help on this I suggest using the discussion forum.
Videos demonstrating features
Creating and editing environment objects: