How do I port an existing 3rd party script to vB3?

[cbiweb]

I have a client who wants to take an existing 3rd party script, and basically convert it into a product for vBulletin. He does have permission to do this, and hired my company to do it. However, the lead developer on the project is not able to do it due to some personal and health issues, so I'm left to do it, and I have miniscule experience with this sort of thing.

So what I'm asking is for some pointers on what needs to be done with a non-vB script to make it work with vB. I believe that most of the script will work as is, once it can "speak to" the vBulletin software. Any help would be appreciated, though I'm not asking for in-depth instructions, just something to get me started. I can't give much more detail in this post, so feel free to PM or email me with questions or other input.

Thanks!