You need to go more into details as your question is extreamly general. Whatever is your plan, what you can do to gain basic and higher level of understanding on how to do social media marketing is to follow tons of free tutorials/videos available in google/youtube.

Only after you get this kind of understanding you can move forward and look for experts to follow on Linkedin.

There is loads and loads of free, valueable info on how to get to know Facebook, Instagram or any other platform:)

Good luck!