Need assistance is creating a Newsletter sign up option in Typo3

I am new to the Typo3 backend environment and am trying to create a newsletter sign up page for our customers. I am not fully sure how to begin within the Typo3 environment. I am trying to install the necessary plugins and it gives me this(link below) warning. Any kind of help would be appreciated.
(enter image description here)(1)
(1): https://i.stack.imgur.com/ywtZZ.png