As a first step, go to www.youtube.com and login via your Gmail account for setting up a YouTube account.
Then, go to your settings which are positioned on the upper-right corner and click on Creator Studio. As a next step click on Livestreaming.
Now, you have to create an account within the account (we know this sounds crazy) for having the permission to live stream. Therefore, insert your first and last name. Then, click on Create Channel.
You are re-directed to a new window where you have to click on Get Started. Now you choose a country of origin and decide on how you want to get your permission code for continuation (orally or as text message). Enter the number of the phone on which you want to receive this code.
As a result, you receive a confirmation code. Insert this code. Now your account is nearly set up. Then go to Advanced Settings. Check that your embedding allowance is ticked off! This is really important! If not, please contact YouTube.
YouTube needs a few minutes for processing your new account. However, it should look like this in the end:
Now, your AdSense account is activated! Congratulations ;)