What exactly do you need help with. The LimeLM web API is not something that you just plop on a server and it does magical things. It's a collection of different scripts that you can use to automate different parts of the order process.
For example: https://wyday.com/limelm/help/how-to-generate-product-keys-after-order/
First, add TurboActivate and/or TurboFloat to your app: https://wyday.com/limelm/help/getting-started/