I would explain in 5 steps
I consider you can build a website with SEO friendly. Now you should make a domain for your site. To get free domain you can follow this link Get Free Domain
If you already have a domain, do this next step Ok!
There are dozen free hosting provide on the internet. I would recommend this sites for your hosting. Although Free Hosting they provide several feature almost same as paid hosting.
The features you can enjoy are:
>>cPanel Control Panel
>>PHP, MySQL, CGI, Perl
>>Host Unlimited Domains!
>>Free POP3 Email
>>FTP and Web Based File Manager Access
>>500+ Website Template
Get Free Hosting Now!
If you don’t have Wordpress yet, you can download here. now you can uploading the file into your free hosting. Set your file according to Wordpress policy.
Before you register to Google Adsense you must write 5-7 article on your site. My suggestion is if you not have article originally you can search or googling, you can find free article according to your site theme, but you should put the writer or/and web resources.
Wait 24 hour to receive email confirmation from Google Adsense. If you are done, now you can add Google Adsense Code into your web page.
This is the last step. If you want have a popular website you should submit into search engine like Google. Submit Site Now and / or directory.