Forgive my ignorance, but can someone briefly explain the Roe Vs Wade thing?

Essentially the ruling stated that a women's access to have an abortion is no longer a federal protection, thus leaving it up to the states to ban it or not. So in some parts of the country it will become illegal, while in others nothing will change. In fact some states legislatures now are writing in their state constitution to make it law to protect abortion.

It just means that every state decides for itself what its law wants it to say. The ruling on it isn't centralized anymore.

No ,it doesn't mean all abortions are illegal what it means is the decision is now state by state so some states can make it illegal and others may not.
It means that the federal government will not guarantee a woman a right to an abortion and it has been determined that abortion is not a constitutional right.
In the states where it is illegal people always have the right to protest and try to elect people in that state that might be more favorable to abortion and overturn those laws.