Since she SkeekS CMS and a number of third-party libraries are outside of your project, they must be connected to the project in the form of third-party libraries. Connect to your project used Vendrikh library. This is necessary to ensure that your IDE prompted you to methods used classes. This greatly speed up the development process.
Specificity SkeekS CMS project (as well as most modern projects) that in the project (usually at the root, but not necessarily) have a folder / vendor, the code that is stored in it can not be changed!
Therefore, the entire project can be grown and stored without the folder.