Ok this may sound completely stupid to all you pro's out there.
I always make my cakes from a mix and add pudding to it to keep it moist. But I hear/see ya'll talking about filings ALL the time....

SO where is the filing at? Do you put it IN the cake or is it like when you stack 2 or more cakes together you use filing instead of icing to put them together? I know this may sound dumb but I just don't have a clue

It's when you stack cakes or if you want a single cake to have a filling, you can tart it (cut it in 1/2) and fill it.

You take the cake and cut it in half. Then you put a damn of icing around the bottom layer (with buttercream icing) then you put filling in the middle and then you put the other layer on top.

The ONLY stupid question is one NOT asked!!!!!! The filling goes in between the layers where the icing normally goes. Or as said before, you can cut your cake in half horizontally and make extra layers for filling.

thank you very much for helping
and for not making me feel so stupid