Like all design jobs, you start with defining the task.
With wayfinding, it’s all about how to get people “from here to there.”
Wayfinding isn’t just one thing.
Wayfinding can be:
Street signs
Subway maps
Office building directories
Historical district ID signage
Hospital mapping
Even the ADA compliance signage required in all public buildings.
Any combination of the above and more.
Or it can be more invisible than an actual sign
Wayfinding is all about traffic flow, whether it’s pedestrian or vehicular.
In the context of, say, a historical museum exhibit that takes up several rooms in a building, wayfinding may be more subliminal than big arrows saying “This way to the Egress.”
The exhibit will have a flow to it, doors or archways, color schemes or visual draws that bring the traffic from entry to exit in a progressive pattern - or at least it tries. Visitors will do their own thing. A lot of studies are done in the museum industry to track visitor traffic. Think “Trade Show.” You want to draw visitors to your booth, or into the next room.
Here’s a really good description of the steps it takes to plan a museum.
Museum Exhibition Design - Museum Planner
I also posted a link in your other post to the SEGD.org website. Check it out. It’s all about Experiential designers and a good portion of that work is wayfinding.