1. Firstly, sign into your Lightspeed account.

2. Then, go to App Store menu and find "DragDropr' in the search filed and purchase the app. After that just click on "Install" in front of it.

3. As soon as you've clicked on "Install" you'll be redirected to the DragDropr login page.

! Make sure that you have allowed Pop-ups in your Browser or disabled the Popup Blocker:

https://www.isc.upenn.edu/how-to/configuring-your-web-browser-allow-pop-windows

5. In the pop-up that appears you are able either to create a NEW DragDropr Account or sign in to your already existing one and choose the needed Project (it shouldn’t have any other integrations). 

That's it, now you're all set.

! If you want to uninstall DragDropr, then just click on "Purchased Apps" and press on "Cancel app" button in front of the needed app.