If you want to install a contributed module, which depends on an external library, and also depends on the Libraries API module, you are on the right page.
Note that installing the Libraries API module and installing an external library are two separate steps, that are independent of each other.
In detail, the steps you need to follow are the following:
Install Libraries API
Please note that, as is described on those pages, the Libraries API module directory should be inside the sites/all/modules directory (or sites/example.com/modules if you have a multi-site installation).
Install the external library
- Download the library
The module that requires the external library should provide a link to the homepage of that library or, even better, directly to that library's download page. Sometimes the module will specify a version for you to download, otherwise just download the latest version.
- Extract the files
If the file you downloaded is an archive, i.e. its file extension is
.tar.gz, you will need to extract it first. On Windows, use a program like 7-zip to extract it. On the Mac, you can use Stuffit Expander. For *nix systems, use the command line:
tar -zxvf modulename-drupalversionnumber.tar.gz. After extracting the file, you should see multiple files or a single folder with the library's name.
- Upload the library
First you need to check if there is a
sites/example.com/librariesif you have a multi-site installation) in your Drupal installation and, if not, create one. Then inside of that directory create a new directory with the Drupal machine name of the library. The machine name should be provided by the module that requires it, sometimes implicitly as in
"Install the(in that case the machine name would be
foo). Upload the library files into the directory you have just created. If the library consists of a directory, which you have just extracted, upload the entire directory into the sites/all/libraries/machine_name directory.
Please note that, as is described above, the external library (unlike the Libraries API module) should be inside the sites/all/libraries directory (or sites/example.com/libraries if you have a multi-site installation).
The external library should not be in the sites/all/modules/libraries directory, which is the directory of Libraries API module (see above). This is a subtle, yet very important difference.
Install the other module
Now you should be able to install the module that requires the external library just like you installed Libraries API above, or as you would install any other contributed module.