Beeping ESC is normal, it means “lights on but nobody at home” If the props were on you might see them “twitch”, I think it does a few milliseconds of power to show the rotation. Same effect after a crash when APM disables itself for safety (something I learnt the hard way).
To power the Navio+ you use the supplied (in the PDB box) 6 wire “Pixhawk/APM” power cable from the small white “DF13” connector and plug this straight into the power connector of Navio+. Besides powering the flight controller it also sends voltage and amperage information (you don’t need that optional power/voltage cable from Emlid when you have this PDB, but if you’ve ordered it anyway you should find it useful for bench testing).
To power the receiver, you go via the servo rail. Leave ONE of the four ESC red wires connected. That means you MUST disconnect the other three. It’s all covered in detail in the Emlid docs link below. Note the tiny crosses X over three of the four ESC wires (a bit hard to see but the text clearly warns you about it):
By the way if you had OPTO ESCs (no BEC) you would take the 5v from the PDB down to the servo rail. So you have lots of options. Oh remember you need the FrSky SBUS to CPPM converter between your receiver and Navio+ because the X8R speaks the newer SBUS language which is not supported yet by the Navio+ drivers.
There are two calibration procedures you should do when you get the Navio+ and have everything connected:
ESC calibration. Follow the APM:Copter docs for “all at once calibration” but read the Emlid docs/forum on how to do this by setting parameters instead of using the Pixhawk “arm switch” (which we don’t have on Navio+). Still easy, just a slightly different technique.
Voltmeter calibration. As documented (with no changes) in APM:Copter web site, but take note that you have to generate about 10A of power before you’ll get an accurate ratio. And don’t worry about readings at low amps, none of the boards are accurate at low amps. That’s why you have to take the setting at about 10 amps.
On that subject there is one thing I forgot to add to the list. Everyone with a battery powered RC model should have a multimeter. I like this one from HobbyKing because it does all the combinations of reading voltages (battery balance lead checking, battery load/performance checking and more) plus it has nice features (at the same cheap price) like a servo tester and RPM meter.
The other thing which is useful when you are playing around the first time, is to have a beeper when the battery is low. Sure the built-in telemetry and other features are supposed to prevent that. But when you’re getting everything setup you’ll easily forget. Then your drone drops out the sky and your battery will have had a dangerously low voltage (not good for health/potential fire in extreme cases). So just get any one of these an hang it off the balance lead, secure it with velcro somewhere, e.g. back on top of the battery strap works well for me. This is the one I bought but there are others which also show the voltage which I’d probably get the next time:
Finally to answer your other question, yes for testing you can easily get all the motors to spin. Just create a “mix” on your Taranis, which takes the throttle input and sends it out on all four channels of the receiver. You couldn’t fly with that as there would be no levelling. But it would help you test the prop rotation and ESCs.
p.s. one other part you need in the toolbox later is an ESC programmer. No worry because Hobby King always flash the ESCs to some recent SimonK build and in a combo box like you bought they should all be the same version. But later you might want to learn how to update your ESCs with this:
p.p.s. The legs fall off that frame quite easily so what I do is loop the three motor power wires through them and cable tie. That way when they fall off they just dangle down (not lost in the grass).