Want to know about web 2 Backlinks

Hello Guys, i heard from a Lot's blogger that web 2 backlinks are one of best method to do Google Ranking. But, i am confused as a newcomer on this subject. So, i want to learn from you guys . I am confused about a matter. Should i write only 1 article on one web such as Blogger (Free web 2) if i make a Blog there, should i post only one article and than make promote or what ever i need to do ? Can you please give me a complete guideline ?