These pages will cover how to install OpenAthens SP in its most basic form. Advanced configuration options are covered in the maintenance section.
No non-standard ports are used. All OpenAthens specific communication is passed over http or https.
OpenAthens SP is very light on system resources and unless you are already pushing the limits of your systems you are unlikely to need to make any allowances.
OpenAthens SP can most easily be installed on the same server as the application you wish to enable access to and the documentation will assume that is the case for simplicity.
You can also use OpenAthens SP to broker access for several applications by acting as a central hub if you prefer.