Welcome to Poker.SE! This question is pretty broad, which is probably one of the reasons it's not had much interest since you posted it. It might be worth trying to ask a more specific question about the functionality which poker players might want in such a tool and considerations when it comes to the differences between NLHE and PLO for example. You may also find SO, Software Engineering or Code Review more helpful for the specific technical questions you are likely to run into when implementing your tool.
With regards to your specific question - which as best I can tell is "Where should I start in trying to build an equity calculator for PLO?" - I would suggest that starting to define requirements for the solution (based upon the reasons why you want to create the tool) would be the logical place to start, as is the case with most software development projects.
You may also want to start thinking about the technology you wish to employ - you say you are a "coding noob", but do you have any relevant knowledge or experience with creating software which might give you a starting point technologically? It doesn't necessary matter (IMHO) whether you start with the most appropriate technology for your task (which I would probably guess would be something C-like as you're looking to crunch big calculations quickly), but it's important it's something you at least roughly know your way around, so that you can actually make some progress at the start and not get demotivated.
If you're interested in recruiting people to help you and broaden your skillset, perhaps post on Meta and ask where you might be able to do this on SE (if anywhere) - perhaps some others here on Poker.SE will also see this question and get in touch.