One of the first things I did w hen I was new was to get on Youtube and Searched "Mountain biking tips". There are several really good channels with entire series of information. It's a good way to get some basic principals in your head. You'll need practice on the trail to realize it, but it certainly helps.
Bike groups, meetups, and stuff like that is a great way to get out with others too.

Your first few rides, just take it slow and easy, but try to get out at least two or three easy rides per week. The amount of time you put in, with rest in between, will greatly affect how fast you learn. Once a month and you'll loose confidence and familiarity in between sessions.