To associate your YouTube Channel with AdSense, you may follow these steps:
1. Login to your YouTube account.
2. At the upper right corner of the screen, your profile picture should be visible, click it then click the Creator Studio button.
3. The Creator Studio menu will be invoked and appear at the left corner of the screen. Turn your head on that side and choose CHANNEL.
4. The CHANNEL menu will pull down. At the center of the screen, check if Monetization is not enabled, you must click the "Enable" button to enable it. When Monetization indicator has turned green, proceed in clicking the Monetization at the CHANNEL pull down menu.
5. A Monetization Status and Guidelines/Info appear at the center of the screen, click the "How will I be paid?" subject.
6. An information will appear below the subject title, giving an instruction. Click the colored blue, "associate an AdSense account" link.
7. More explanations will appear, you may have time to read them and/or click the "Next" button.
8. The confirmation of email page will be invoked, click the blue button "Yes, use my [gmail address that you use to access your AdSense account]".
10. If the association is successful, a result should come out telling you that the association is now approved.