On the "Home" section of this site, tap "Install iTweaker."
You will receive an alert asking you to allow the installation, tap "Allow."
This will redirect you to your device's Settings app. Once here, tap the "Install" button on the top right of your screen.
Now, you will be asked to enter your device password. This is just to ensure that you want to install the app. Just type in your password and follow the rest of the instructions, they are pretty self-explanatory. Once finished, you will see iTweaker on your homescreen! Now, just enjoy the app!