Egg Crack Help

Okay so it says MD4 hashes and SHA-### Hashes... i would like to know what they do and how to use them please

They are for cracking leaked MYSQL databases. When passwords are stored in a database, they are hashed (so something like "test" hashed with MD5 turns into "098f6bcd4621d373cade4e832627b4f6") so if the database gets stolen, nobody can figure out the password easily. What EggCrack does is brute force the hash by guessing the password continously until the hashed "guess" is equal to the hashed password. That means the password is equal to the guess.