At the simplest level, create 2 or 3 ABP's and you have the beginnings of it. Take a look at the document to see what else you might need to do, changing default calendar permissions, create some transport rules, secure OAB's, remove some ECP options, there's a lot of scope. We are not going to produce a step by step on how to do it, as there's really no one-size-fits-all approach to this.
I would warn anyone that thinks ABP's ARE multi-tenancy to think again. They solve one of the problems (directory access) you need to solve when building a multi-tenant platform, but they alone are not the entire solution.
It's not super simple, which is why we wrote the guidance, and we worked with control panel vendors, who have the skills and experience already, and who offer ready made solutions. If you don't have the skills in-house today, don't have a desire to develop the skills inside your own company or need to get to market fast, you might wnat to choose one of the vendor solutions we have validated.