How to add new repository in CentOs

I am trying to install readR package from R on EC2 instance.

I found a solution on this post:

I would like the script for CentOS but the answer is for Ubuntu:

[1] apt-get update     # refresh
[2] apt-get install software-properties-common
[3] add-apt-repository -y "ppa:marutter/rrutter"
[4] add-apt-repository -y "ppa:marutter/c2d4u"
[5] apt-get update     # now with new repos
[6] apt-get install r-cran-readr

Below is my attempt to translate, I understood line 2 is not necesary in my case, and what I am missing are the two lines allowing to add repositories in CentOs:

sudo yum update
sudo mkdir ppa:marutter/rrutter
sudo mkdir ppa:marutter/c2d4u
sudo yum update
sudo yum install r-cran-readr

Help much appreciated !