Project management really boils down to a few simple concepts.
Decide what needs to be done (scope).
How much do we have to spend (cost).
When does it have to be done by (schedule).
Anything beyond this is defined by your individual project.
Estimating, risk management, change control; all of it is dependent on your situation. Short term project where you control most of the input? Probably not a lot of risk or risk management to worry about. History of similar projects? Estimating (both cost and task duration) is probably going to be straightforward. Requirements and/or scope fairly well defined, or limited number of stakeholders? Change control will be pretty easy.
It's as each of these factors increases in complexity that you have to start getting more in-depth in terms of processes. But at the base level, if you have a way to track tasks, cost, and schedule, that's all you need.