On the YouTube setting, you can turn on the monetization box. However you don’t get ads immediately. YouTube requires 10,000 views minimum before ad can starts appearing. That’s the first step.
Second step is, you need to sign up for AdSense. Try not to sign up via Adsense site (Google algorithm will check whether you have bad history or connected accounts that may jeopardise your chance). Sign up via YouTube (once you go turn on the monetization setting, there will be link to sign up)
Third step, make relevant and think like your future sponsor. You can make a prank or gaming video, but would your industry sponsor would like those type of video?
Fourth step, spend sometime on good SEO strategy.
Fifth step, do frequent social media sharing.
Sixth step, be patient, no quick and easy way for this. Unless you are a popular celebrity or your video is very viral and unique.
Seventh step, wait, Youtube/Google algorithm will try to match the advertisers and your youtube relevancy/rank/content before pushing ads to you.
Note, making Adwords Ad is useful, but if you are starting out why would you want to spend money on Adwords Ad (and it’s not really straight forward, unless you know a specialist) Do not get tempted with Google free 75$ credit for Adwords. If you cannot target it well, money will be wasted.