There are a few resources that might help kickstart your progress. The long and short of it is that Tulip has connected to every ERP under the sun, but the solution differs a bit based on your specific ERP. here is a really good article that walks you through the process to understand the best way to connect with your ERP specifically.
We have a app and connector function (link) pre-made in library that you can download designed to connect to Microsoft dynamics that might be a decent example of what that connection might look like, but like I said, the solution for each ERP is a little different. I reached out to our team that does one off connections to lots of different systems to understand the process for 3S specifically, and I will update this thread when I have a little more detailed answer about that ERP specifically.
We don’t rate limit any of our connectors to other systems, so 1 call/second is more than possible. This is usually bottlenecked by the speed at which your ERP can respond, so if you are asking for a lot of data that can be a bottleneck at times.