You can download a trial of the app here:
Android (4.2 and up):
Windows (8.1 and up):
After downloading the trial, you can enter your license info within the Campaign Logger app.
There's also a web app, and you get access to that when you purchase the bundle. There's a separate login email for that I send you.
So to hopefully clarify, GumRoad is not our app. It's a payment app. Campaign Logger is a completely different app than GumRoad - we're just using GumRoad's service to handle payments.