If you want to take advantage of the new ArcGIS Enterprise Builder to rapidly install the software in a single machine, a pre-requisite is to have two licenses files or authorization files with the *.ECP extension. You need one for Portal and one for ArcGIS Server. However, the process of creating these files is very complex, specially if it's your first time using Esri's software. This how-to guide will explain you how to do so.
This process assumes that you already have and ECP code, that is someone in your organization has provided (via email for instance) a code like ECPNNNNNNNNN both for Portal and for Server (it should have nine numbers).
However, If you want to use the Enterprise Builder you have to provide the following information:
Unfortunately what you have is just an ECP code. How do I build or get the ECP file?
Firstly, you have to copy and paste in to different TXT files the ECP code. Just that, but It's also important to save the files with the txt extension and to save the in two separate files since you have to create two distinct ECP files.
Secondly, with these two files generated you have to go to your MyEsri account and click in the following link, Operations in a Secure Site, on the bottom right corner of your Licenses tab. You can see my screenshot below but is in Spanish sorry
Once there you just only need to click the "Select File" button and MyEsri will create the Authorization.ecp file for you.
Hopefully, you will finally end up having the two files needed to continue with the ArcGIS Enterprise installation process.