I would recommend checking out this article here: https://help.adblockplus.org/hc/en-us/articles/20614958018707-Check-if-Adblock-Plus-is-installed

if you find you do not have ABP installed, you are welcome to install it at any time. You can see how to do it here: https://help.adblockplus.org/hc/en-us/articles/1500002320801-How-to-download-and-install-Adblock-Plus