To exchange encrypted messages with other users, you must first generate your own pair of keys. It consists of two parts:
Public Key. This key is used for encryption. Distribute it to your communication partners, so they can use it to encrypt files or messages for you.
Private Key. This key is used for decryption. Use it to make encrypted files or messages from others (or yourself) legible again.
Important: Access to the Private Key
If others gain access to your private key, they can decrypt files and messages intended only for you. Never grant others access to your private key.