Step 1 install the module - OShop/OShop.PayPal GitHub Wiki
At the time of writing this wiki, there is no official release of the OShop.PayPal module. If when reading this wiki there is an official release available, you may choose to download and install that instead.
The instructions below cover installing the latest available development version.
Download the module ZIP file
Navigate to the home page of the GitHub project fork, or the parent GitHub project OShop/OShop.PayPal. Under normal circumstances, you would choose to install the module downloaded from the parent GitHub project OShop/OShop.PayPal, unless there is a feature which is only available in a forked project.
(1) Click the 'Download ZIP' button and save it to a location on your computer where you can easily find it.
(2) Extract the contents of the ZIP file.
(3) Rename the extracted folder to 'OShop.PayPal'.
(4) Copy this folder and its contents into the 'Modules' folder in the root directory of your Orchard instance.
Enable the OShop.PayPal feature
(5) Navigate to the features tab within the 'Modules' section of the Orchard dashboard.
Orchard Admin Dashboard > Modules > Features
(6) Locate the OShop.PayPal feature and click 'enable'.
(7) If everything is OK, you will see a "OShop PayPal was enabled" confirmation message. The OShop PayPal feature depends on the OShop Payment feature, so you will also see "OShop Payment was enabled", if it was not enabled already.
Visit the Orchard documentation: Enabling and disabling features for more information.
(8) You have successfully installed the OShop.PayPal module for OShop in your Orchard CMS instance. It is ready to be configured.