Sign in to YouTube on a computer or using the mobile site. Try any action that requires a channel, such as uploading a video, posting a comment, or creating a playlist. If you don't yet have a channel, you'll see a prompt to create a channel. Check the details (with your Google Account name and photo) and confirm to create your new channel.
A single username and password gets you into everything Google (Gmail, Chrome, YouTube, Google Maps). Set up your profile and preferences just the way you like. Switch between devices, and pick up wherever you left off.