Welcome to X-Plane! The ultimate flight simulator, constantly growing and evolving, thanks to you and developers.
We hope you've read the manual (yes, it's actually important!), and just about every question that has been asked has also been discussed or answered in Youtube videos. There are also many "how to" guides and suggestions for X-Plane add-ons on YouTube as well.
One site you definitely should grow accustomed to is X-Plane.org, commonly referred to as the "org". The X-Plane.org community is the biggest for X-Plane and has almost everything X-Plane related you could think about. If you don't find what you want there, there will likely be discussions and/or links about it in the forums.
If you're trying to grasp using X-Plane 11, you may find the flight school a compelling guide if you are new to X-Plane, or want to improve/refresh your flying knowledge.
Before exploring what X-Plane.org has to offer, take note that there is a rule in the forums in which you're required to post two answers before being able to create new topics. Read the forum rules to get a better understanding of the overall expectations and customs of the .org forums.
In addition to the large community housed within the forum, X-Plane.org also is known for its store. Many aircraft, sceneries, and addons are sold there. A download repository in the forums containing hundreds of thousands of user modifications, freely downloadable, is also available to registered members of the .org. There you will find many major airports (and thousands of smaller fields), aircraft, and other plugin based work uploaded for, and created by, the community.
If you cannot find what you're looking for, search in the download section. If you still can't find what you are looking for, do a quick Google search. The X-Plane.org's built in search functionality is notorious for it's unreliability and error-prone results.
X-Pilot & X-Aviation
Another store to check out is X-Aviation. Home of the IXEG-737, which is widely considered to be the hallmark of X-Plane aircraft simulation, on the turboprob side, a noteworthy addition to your hangar is the SAAB 340; arguably one of the best turboprop simulation - utilised by real world airlines and SAAB themselves.
For most airports submitted in the Download repository, you will most likely need an additional library for the airports objects. The libraries are “collections of objects” that developers use, and you will need them in order for your airports to work. This master list outlines almost every X-Plane library known in the community, and we suggest you to bookmark this to stay up to date on the latest library revision/version.
We are establishing a platform for developers and users to meet the community's needs of a neutral and independent platform for all things x-plane. We now have the editorial, the store and a forum for discussions and freeware. (follow the links at the top of the page)