Multirotor guide

0. Setup hardware

Balance props and motors, install FC on a vibration-damping mount if possible.
Ensure that your motors are mapped correctly because it is not possible to remap motors after installation: Verify that motors #4 and #2 are in the front left and right positions, and #3 and #1 in the rear left and right positions, respectively.

1. Getting your flight controller ready.

Download latest configurator from here
Flash newest iNav with full chip erase option selected
Do the advanced 6-point sensor calibration
Select your Mixer. Most common ones are already available as presets. For exotic setups, see Custom mixes for exotic setups; if you don't do this, you will not see any motors in the motors tab.
Be sure the model moves on the configurator as it is moving on the bench. If not, adjust board alignment from the Configuration tab
If you have a magnetometer, you may need to attach a battery for magnetometer calibration. Rotate the quadcopter 360 degrees on all 3 axes.

2. Configure your TX

No special mixers have to be applied on the TX. Just bypass all the channels as they are to the FC. Set trim on your TX to zero. Use subtrim to adjust your TX midpoints to be precisely 1500 when Roll/Pitch/Yaw sticks are centered. You can check the input values in the Receiver tab in iNav configurator. All values should be in the range 1000-2000uS.

3. Tune your copter's Pitch/Roll/Yaw/Level PIDs and other values

Many presets are available on the specific configurator tab and they mostly represent a good starting point. Be sure to load the correct present and double check the applied configuration.

Default values for different type of aircrafts

4. Trim copter to level flight

DO NOT USE TRIM on your Transmitter to stop your copter drifting. Use board alignment settings or accelerometer trim stick combos. You can use RX stick combination to trim the quadcopter: Controls

5. Check your sensors

If any, be sure the baro readings are correct and be sure the barometer is shielded with some foam to avoid to be disturbed by the air pushed on it by the propellers.
If a magnetometer is in use, be sure to check it is providing the correct heading information. After having calibrated it (outside, far away from buildings and parking lots) be sure that when you point the multirotor nose to the north the heading is 0 and it still is around 0 even if you tilt the multirotor a bit on pitch and roll axis. Be also sure that the magnetometer is placed reasonably away from interference sources (such as power wires). Having a good compass reading is crucial for navigation function to work correctly.

6. Setup and verify failsafe on TX and iNav

Guide for setting up failsafe

7. Determine and set hover throttle

To let the altitude hold controller work correctly, you need to input your hover throttle (the throttle you need to apply to make the multirotor hover) into the nav_mc_hover_thr CLI variable or just set it via the configurator configuration tab. If your copter jumps/rises when you activate altitude hold, reduce your nav_mc_hover_thr a bit. If your copter falls, increase it a bit; fine tune until there is no jump or fall when activating altitude hold.