In the software click on the Tools section. Choose advanced calibration from there. You did download and install both software tools as well as the manual, did you?
If you mean calibration by doing the compass dance, that's not enough and will not tell your Phantom the exact declination and the specific compass error at your position. The compass dance is needed when you move to an entirely different location. If you stay in the same area you shouldn't need a compass dance every time, although it doesn't hurt and it will give you peace of mind. The basic and advanced calibration in the Naza Assistant is the first thing you need to do before flying for the first time. Although the phantom is expected to fly straight out of the box, many people, including myself, found that after the advanced calibration things behaved finally like they should.
While in the software, take the opportunity to setup the IOC and FailSave (Return to home) switches. ~Then, after you did the advanced calibration, power up the quad, wait for 2 sequences of green lights, wait until it is only blinking green every 2 seconds. THAN do the compass dance one more time. And now you're good to go.
If you set the IOC switch you can easily check if your Phantom has written the HomePoint correctly (and that you can be sure it will return home when a FailSafe happens, unless your battery suddenly dies or connections are loose, of course). Just set the S1 switch to HomeLock and direct the quad away from you diagonally some 30 yards. Then move the pitch stick towards you. Is the quad coming towards the home point? If so, everything will work concerning RTH and GPS mode (again, unless there's a malfunction somewhere). I do this check every time before i start my flight. If the Phantom doesn't behave like it should, land and do a basic or advanced calibration (on the PC). Always do the compass dance after recalibration.
And reading the manual wouldn't hurt a bit, but I presume you do, like we all do, now don't we?
I'm a sucker for manuals when it comes to remotely controlled devices. Just suck up every bit of knowledge and browse the web for more info, and then some. The responsibility we have when something goes wrong is underestimated by a lot of people I'm afraid.
Not here of course, that's why we joined the forum in the first place
Try out the Return to Home Switch, I know it is odd the first time, to let the Phantom control itself to home, but do it, AFTER you did all of the above. Learn how the IOC works. It might save the day when the day comes, and it will come someday.
Yesterday I was flying out 200m and was near a tree line. The camera connection was gone because of the distance. I couldn't tell if the Phantom was facing me or the trees. I couldn't tell if it was 30m in front of the trees or right under. I didn't dare to go forward or backward or up. Afraid that it would hit the trees. Only thing to do was switching to HomeLock. Lucky that I had that activated. With HomeLock the quad just flew back to me in a straight line, no matter in what direction the nose was pointing. Saved my day, I'm sure I would have flown it into the trees because I always gamble wrong, certainly in these situations.
Bit of a long post but what the hack, I'm here anyway so why not.