Hi, and welcome to PF.
As it happens, Hooke's law is not that difficult to understand. Have you played with a Slinky before? If so, then you probably know that if left undisturbed, it sits at a certain length. If you compress it and let it go, it will try to return to that length, but will undergo damped oscillations. If you stretch it out and let it go, the same thing will happen.
The force that acts to push/pull the Slinky back to its original length is called a restoring force, and Hooke's law says that this force (F) is proportional to the displacement (x) from the original length, or:
F=-kx
Here, k is the proportionality constant (unique to each spring), and the minus sign indicates that the force points in the opposite direction as the displacement.
In other words, if you displace the spring this way: --->
the restoring force pulls back this way: <---
and vice versa.