How does apt work Linux?

All packages required by the package(s) specified for installation will also be retrieved and installed. Those packages are stored on a repository in the network. So, apt-get downloads all the needed ones into a temporary directory ( /var/cache/apt/archives/ ). They will be downloaded from a web- or a ftp-server.

What is sudo apt?

sudo apt update is the command used to download and update the package information from all of the configured sources.