There's a search at the very top of this forum layout, looks like a magnifying glass. If you type "Creo Post Processors" there you'll get a list of many past inquiries about this very thing. Here's one I responded to a while ago that was about a machine that sounds very similar to yours, but it doesn't have a "real" solution, just links, etc.
https://community.ptc.com/t5/Manufacturing-CAM/Post-processor-for-Fanuc-6-ProtoTrak-SMX-3-axis-CNC-mill/m-p/930373
In brief, you'll have to look into how to set up a post processor for your particular setup. Creo does come with a bunch of default ones, or at least it did, so you just have to look for them. They might be shown to you by default, I'm not so sure. I configured my posts decades ago, so only work with the ones I have built.
