• Go to http://www.adwords.google.com home page. Click on Start now. See below:
• Next step sign in with your Google AdSense account. See below:
• Next set up time zone and currency. Do it carefully because it can not be changed after being set up. See below:
• That is it. You have successfully create your Google AdWords account. There is a one-time $5 charge to set up your Google AdWords.
• Next sign in with your Google AdSense account if that is what you chose to sign up. Click at Create your first campaign. See below:
  
• Next name your first campaign and first ad group with keywords-targeted.
• Next choose a locations, languages, and demographics for your ads.
• Then create your first ad. Fill in the headline, ad descriptions, and your URL.
• Then select your keywords, set daily budget, default CPC (cost per click) bid. Don’t set default CPC content bid if you are new to Google AdWords.
• Finally save your campaign. Within minutes your ad will be active and running.

Learn more about Google AdWords here.