Hi. My question is follow: what elements do I need for install a wisp from nothing?
I worked with mikrotik before, but I never worked as ISP.
Thanks

MikroTik: How to Start a Wireless ISP
http://www.dslreports.com/faq/wisp/2_How_to_start

You should also consider hiring a consultant if you are unable to understand some of the fundamentals provided in above links.