TOPC
Aircraft stability in its multiple dimensions is not an easy subject.
Design engineers often go grey trying to meet present design requirements and Test Pilots are often hard placed to sort out the designers' shortfalls..
The stability we are most familiar with is the steering stability of a car. You have to apply a small force to the steering wheel to make the car depart from its positive stable desire to continue going in a straight line. Adjustments of the stability to be negative can make the car very hard to handle. It will want to depart from the straight line incessantly and you have to fight it all the way. Flying an aircraft with negative pitching stability is almost impossible for any lengthy period. If an aircraft has negative directional stability like the car it will always be trying to turn round to go backwards.
New aircraft designs often go pear shaped when stability effects interact from one dimension to another.
Best way for you to get some comprehension of the subject is to initially narrow your approach to one dimension such as that of an aircraft pitching - called longitudinal stability. There are easy to find websites which will provide you with the basics.
For some it may become addictive and they may be the ones who end up aspiring to become aeronautical engineers.