build website+ sing up with google adsense + place adsense code on your website = website with adsense
i could sit for hours and ponder why people ask such ambiguous, clueless questions like this. do lots of reading, build a web page, promote your site and make it your life, then ad adsense. if you do it all, and do it well, you might start seeing a slight income by the end of the year.
the easy and cheap way... sign up with 110mb.com or my5gb.com ( free hosting ) go to http://www.freecsstemplates.org/ choose a template , edit your template , upload the sites to the server , sign up for Adsense...
If you want to make a free site, then go to blogspot. On the other hand, if you want your own domain. Then you will need to buy a domain + a hosting. Then I suggest you make a wordpress blog. If you don't know how to do all this stuff, then you can hire someone at freelance site to do this work for you.
The simplest way is to open an account at blogger.com, and then build a blog with several post. Then use the blog to apply for Adsense.
go godaddy register a domain. ($7 to $9 ) rent a Cheap Shared Hosting ($3.24/Month) upload your website to hosting. when your web site has plenty of content apply for adsense. if your site not have content, don't submit your apply.