Sometimes there are a lot of buses in one station.
The Simple Answer
There’s a big sign on the front and sides of the bus that tell what route that bus is taking. It’s very visible at a station or from a bus stop.
The More Complicated Answer
At train stations, there are physical signs at bus spaces telling you where a bus will be. Notice the sign over the sidewalk matches the bus.
If you’re unsure, you can ask the driver. It is well within protocols to ask the driver where the bus is going.
A bus will never change their route number while on the route. This 30 bus goes from Lavista Road to Lindbergh Center Station back and forth. If you need the 30 bus, this is the one you would get on.
There’s another number on the bus that usually four digits. This is the bus number (as opposed to the route number) and indicates which physical bus this is. I think it’s also on the roof to track buses by air. Just ignore this unless you play stupid games like I do where you want to ride every bus in the fleet. LOL
The Details
It’s just as easy as you think. Find your route number and get on.