You can either download the ZIP file from WordPress by clicking "Download" or install the plugin directly from the WordPress admin panel.
Once you have downloaded the ZIP-file, just upload it to your blog ("Plugins" -> "Add new" and click "Upload Plugin" in the upper left, then click ”Install“).
If you download Blog2Social from your WordPress administration panel click on "Plugins" -> "Add new" and enter ”blog2social“ in the search field in the upper right corner, then click on "Install Now".
Now it appears in the left hand side navigation menu.

A comprehensive manual for installing and using Blog2Social is available on the Blog2Social website.
Tags: Blog2Social, install