The username is a unique identifier of your account on this and all the other instances. It's as unique as an email address, which makes it easy for other people to interact with it.
I am at least 16 years old and agree to the <x id="START_LINK" ctype="x-a" equiv-text="<a class="terms-anchor" (click)="onTermsClick($event)" href='#'>"/>Terms<x id="CLOSE_LINK" ctype="x-a" equiv-text="</a>"/><x id="START_TAG_NG_CONTAINER" ctype="x-ng_container" equiv-text="<ng-container *ngIf="hasCodeOfConduct"> "/> and to the <x id="START_LINK_1" equiv-text="<a (click)="onCodeOfConductClick($event)" href='#'>"/>Code of Conduct<x id="CLOSE_LINK" ctype="x-a" equiv-text="</a>"/><x id="CLOSE_TAG_NG_CONTAINER" ctype="x-ng_container" equiv-text="</ng-container>"/> of this instance
A channel is an entity in which you upload your videos. Creating several of them helps you to organize and separate your content.<x id="LINE_BREAK" ctype="lb" equiv-text="<br />"/> For example, you could decide to have a channel to publish your piano concerts, and another channel in which you publish your videos talking about ecology.