Please don't feel stupid, we all had to learn and are still learning.
If you drive a Parallel reasonant circuit with a voltage source, the source has a low resistance and so the voltage across the L & C is fixed at the voltage of the source. So if you vary the frequency, there will be no reasonance.
But if you use a current source, it has a very high source resistance so the voltage across the L & C will rise to a peak (ie. reasonate) as the frequency is brought to the reasonance point.
For a series reasonant circuit, the same applies in reverse. If driven by a current source, the current is fixed at that of the source. But if driven by a voltage source, the current will peak at reasonance.
I hope this helps, if not, don't be afraid to ask for more advice.
Len