Method 1: Installation via Extension Installer:

1. Download the package worldpay-business-payment-x.x.ocmod.zip
2. Login to your admin panel
3. Go to Extensions > Extension Installer
4. Upload this package
5. Go to Extension > Payments. Find Worldpay Business Gateway
6. Click Install
7. Click edit and setup the payment module.

If you do not find the extension or unable to install extension via method 1, follow method 2

Method 2: Installation via FTP (Filezilla)

1. Download the package, and extract the package in to your local desktop. You will find upload folder. 
2. Within the upload folder, you can see admin and catalog folders
3. Drag these 2 folders to your server directory via filezilla , such that the folders gets merged with the existing admin and catalog folders.
4. After uploading these 2 folders in to your web root directory, open the admin panel
5. Go to Extensions > Payments Section. You will find Worldpay Business Gateway, Click on Install button and then click on edit to make the configurations.