What is and how to use pulseIn and pulseInLong in an arduino code

Hi everyone as shown above, I have no clue how to use and work with both types of pulses. Can you help me with this problem?

Thanks

Google to the rescue:
https://www.arduino.cc/reference/en/language/functions/advanced-io/pulsein/
https://www.arduino.cc/en/Reference.PulseInLong

I didn't understand that. That is the only reason why I am asking the forum.

The Arduino reference documentation is designed for beginners. If you have problems understanding that, it will be extremely difficult to rectify that here. You need to help out by telling us what specific parts of the documentation you don't grasp. But "no clue" may mean that you are trying to move ahead too fast. Programming is like math, you can't skip grades.

Also, you never specified your "problem". What are you using it for? What pulses?