Being new doesn't matter so much, it's OK. It sounds like you are an experienced developer, but do you have any experience with Bitcoin/Litecoin integration?
I don't, but I read about it and it seems pretty straightforward. I've integrated dozens, if not over hundred, of different APIs before.
Would you be using a shopping cart software suite, or making a simple custom solution?
I know people have provided open source plugins that are floating around on the litecoin forums... I think for OpenCart, Woocommerce, and maybe WordPress. Perhaps this could give you some direction if you've never integrated Litecoin payments.
I don't think you need even 5% of features and complexity provided by full-featured e-commerce solutions, so I'm opting for a simple custom solution. Two reasons:
It will be easier for your users, as the interface would be designed especially for the purpose of purchasing coins, instead of trying to tailor some complex engine.
Security. Wordpress had countless critical security flaws in its history and I don't really trust it that much. I don't know about OpenCart, but every layer of 3rd party complex software provides unnecessary risks of critical bugs occurring sometime in the future (and if you'd use less than 5% of its features, I would call it unnecessary).
My plan on working with litecoin is to run a local instance of litecoind server (that's also required for that OpenCart module which you linked to) and talk to it over JSON-RPC protocol. That's as simple as it can be.
