Follow these instructions to perform a clean install and configure Subscription25
Install Subscription25
You will find the latest installation link here: Install the latest Subscription25 version
Assign Licenses
Assign Subscription25 licenses and Permission Sets to any user in your org that will work with Subscription25 Assign Subscription25 access
Post install steps
Perform the Post Install Steps
Migrating to a Sandbox
If you have Subscription25 installed on your production org, and you create a partial sandbox, Subscription25 will most likely not work properly. This is due to not all configuration records being copied to the sandbox. If you want to maintain your production org's Subscription25 configuration, there are several options:
Create a full copy sandbox.
Create a partial sandbox and migrate all your Subscription25 config data from production to the new sandbox.
Next Steps
You may now proceed to Set up Subscription25