@off_grid_living@twtxt.net There are probably many extensions for Apache2. Nearly all of which you don’t need. Maybe libapache2-mod-php* if you want to make use of PHP.
Typically, systemd will automatically start your webserver during system startup. Your package manager (apt) does not prompt you, because the package maintainer has chosen some defaults for you which works with the rest of the system. So there is simply no need. Why would you want to change the installation directory anyways?
Also, right after installation, I’d assume that Apache2 is automatically started. If you want to start Apache2 by hand, you can sudo systemctl start apache2, there are also the stop and restart verbs.
The tutorial linked by @prologic@twtxt.net seems a bit outdated to me (old Ubuntu version and SysVInit), you might be better off with: https://ubuntu.com/server/docs/how-to-install-apache2 Even though, that’s probably also not so beginner-friendly.