Newton's 1st law

In 8th grade, we were taught about Newton's Laws and learned that his first law stated that an object in motion stays in motion and an object at rest stays at rest until a net force acts upon it. I wasn't really sure what this all meant in 8th grade, but learning about his laws more in depth in physics helps me to understand his laws a bit more. According to Newton's 1st Law (law of inertia), every object continues in its state of motion until acted upon by a net force. The object's state of motion is either at rest or at a constant velocity. At this state, the object's net force is zero. While at a sleepover, we piled the drink bottles up on each other, and they were all at rest. Because of Newton's 1st Law, the bottles stayed at this state of motion until a net force (someone's hand) broke this state and pushed the bottles over. This incident happened a while ago and was something we did only for fun because we were bored, but it is interesting to know now that there is physics related to this.