When I started reading some programming Architecture books, I noticed that there's a lot of arrows used between objects and I couldn't identify what they mean. So I made it to make sure I know what these arrows mean so I can understand the diagrams better.
One way to understand the Software Design and Architecture, and being able to communicate with other engineers what you're trying to do is knowing what these arrows mean.
I have consolidated what these arrows mean from the Design Patterns book from https://refactoring.guru His book was so easy to understand and it doesn't feel overwhelming when reading it - I highly recommend it for other engineers who want to study about Design Patterns.