In all likelihood, you've installed Apache using
apt-get - this downloads and installs pre-built binary packages, which are customized to do things in the Debian way - file locations, default config files, upstart scripts, and niceties like logwatch are handled for you.
Compiling the software from source in Ubuntu is definitely doable, but you're then on your own as far as applying future patches and version upgrades - which will also need to have the connect-method-over-SSL patch applied, then re-compiled from source (no more
apt-get upgrade). And you'll need to stick to the current version of Apache instead of the one your OS came with, as Ubuntu backports security fixes from new versions).
Also, you'll need to have the understanding that anything on the internet related to an Apache install on Ubuntu is probably no longer applicable to your install of Apache - file paths, config files, compile options will all be different.
If you're set on this approach, run
apt-get install build-essential then follow Apache's guide here. It may not be worth the headache - have you considered just putting up something like stunnel to handle the SSL part to allow for the connection to hit Apache on port 80?