To be absolutely certain, you should:
* Consult your owner's manual: This is the best resource, as it will have a diagram showing the exact location.
* Look for a large rectangular box with numerous fuses and relays: It will likely be clearly labeled.
If you can't find it using these methods, a search online for "1994 Ford Ranger fuse box location" with images might help you visually identify it. Pictures of the engine bay of a similar year model could be particularly helpful.