Horizon put out a series of videos that show you step by step how to install the receiver all the way through programming rates and flight modes etc.
.
.
I followed every step on my ExtremeFlight Slick 580 and it worked great.
Make sure you set up the AS3X screen in your transmitter so you can visually see what the actual gain settings are that you are getting, and you can not use the relative setting with this because it will mess up the flaps and gains, so use absolute.
This great work will surely attract a whole new generation of readers who study Sigmund Freud.
Simple answer for reducing speed, turn off the auto-throttle.
The units are very prone to corrosion, ensure the doors, solenoids and locking pin all are clean and lubricated.