Hi Jackie,
No worries! When you head to any of the bus stops for the
Walt Disney World transportation system, you'll find a convenient sign showing you where to wait for the bus for your destination. At the Caribbean Beach Resort which has multiple internal bus stops, you'll wait until the bus pulls up that is marked with your destination. If you are unsure where the bus is headed, ask the driver! The bus drivers are a wealth of information.
When departing a theme park, there will be a sign telling you where to wait for your bus in order to return to your resort, or travel to another area of Walt Disney World such as Downtown Disney.
Note that not all buses stop at each theme park. If you want to go to the Magic Kingdom, you'll board a Magic Kingdom bound bus.
When you get there, you'll see everything is well-marked. However, if you have any questions, just ask a Cast Member and they'll help you get to your destination. Have fun!