Hi.
I installed ue4 today and played with it around a bit. After I got a hang of it, I decided to get some more content from marketplace and this is where the problem occurs.
How am I supposed to add a project in the Library so I can add the downloaded content from marketplace in it?
Thanks in advance
If you download content for Unreal engine, you should open it up as its own project. From the content browser you will be able to right click>Migrate. It will ask you choose the content folder to migrate to, and will auto-import any assets referenced in the item you are trying to migrate.
Some assets from the marketplace will actually be in your Library, under Vault, and have the option to “Add to project” Then you just choose the project you want to add it to.
Thanks for the reply. I menaged to get things done but now I am facing another problem.
I created the project as AquaGames said and then migrated the content into my project. I created some landscape and whenever I try to use meshes or materials or anything else, it just loses the material and it gets default material (checkerboard white and gray).
The only content that works is from Water Panes. It is the only one that has “Add to project” button and the other two have the button “Create project”.
Hopefully somebody knows a solution to this.
There are two ways how you can get stuff from one projects to another one ->
You have to make sure that you keep the folder structure, because otherwise you will lose some references. 
So you will have to create the project - use one of the two ways showed in the video