What Techniques are on show here?

[SeventhWave]

Hi guys, new to the forum here, and although I have played guitar and drums for years I've only recently become interested in singing. I was just wondering if you guys could take a minute to watch this vid and maybe explain some techniques or point to the resources available where I can learn to sing properly/ produce distortion etc?

excuse the "nineties" feel of the vid

I'm really interested in knowing how he can switch between the clear clean vocals at the start and transition into 2:25 where he has a very aggressive yell/rasp to his voice, where at 2:50 he goes full on with this. Also, from 3:15 till the end he starts to incorporate a very rich distortion on certain words in the phrase, finally ending in a scream, but what type? false? fry?

Basically how is he doing this? And can you point me in the right direction to start learning these techniques/styles? Any help would be greatly appreciated.