second tier linkbuilding

I dont understand how to do this and why should it improve the SEO of my moneywebsite

As I have understood it works like this

Find an autority website, then ask him to let you write an article on its website

Well, once you have made this find other high Autority website in your niche and ask him to write a guest post, that points to the FIRST website you have written on.
Reapet the process with other Autority Website.

Is that how work to build 2 link tier

My question is

Why to point to a website which is not yours, and not to point direct on your money website ?

Technically yes, but as you go higher in your tiers, you could relax your criteria on what you deem as a quality link.

I would buy quality high authority links from a reputable source for your Tier 1 link building and then use Web 2.0s, social bookmarks etc., for your tier 2