You plug IIDTool into the OBDII port above the driver side footwell, navigate to the suspension menu, change your suspensions height (front and rear axles separately, should you wish to raise your butt more than your nose, for example), unplug the tool and throw it in the glove box. To go back to stock height, you plug it in, lower your suspensions' height by whatever number of inches you raised them originally - or just choose the saved factory settings if you aren't sure - unplug it and throw it back in your glove box.
You will drive permanently at that chosen height, at any speed, until and unless you re-adjust the suspensions. How much you can raise them depends on your suspensions' initial calibration values, which are stored in the EAS ECU and different in every vehicle (and every corner of your car.) The IIDTool will read those values, and based on the highest one it will not allow you to raise the suspensions beyond a calculated safety threshold. This is to allow the car's Terrain Response and height settings to still do their thing without generating suspensions errors because you've hit the upper limit of the sensors. So, with the IIDTool some owners may be able to achieve a 2.5" lift, some only 1", although most seem to fall somewhere in between - usually 1.5 to 2" is fairly common.