On this Long Beach Chant site, you will find a few videos, but other websites have spent a lot more time (and money) in developing professional online teaching resources:

https://www.gregorianchantacademy.com/

and the Youtube channel : https://www.youtube.com/c/GregorianChantAcademy

Please start with this excellent 5-minute video:

Do you prefer a private teacher, or to organize a group teaching event, either online or in-person? Angela Maria Rocchio’s International Chant Academy is our recommendation: https://www.chantacademy.com/

… Or you just want to learn the most ancient and meaningful chants of the Gregorian tradition?

This podcast may be what you are looking for : https://www.floriani.org/podcast