Hello,
I am a relatively new investor in Bitcoin, and recently I have been reading about a fork to Bitcoin gold. My understanding is that everyone who owns Bitcoin receives the equivalent number of coins in the forked currency, once the fork takes place. Is this correct?
Yes, as long as the wallet you have your bitcoins will support bitcoin or better put it on a wallet that contains your private keys so that you will not have any troubles at all.
Do I have to store my Bitcoin in a specific wallet (I might be new, but I'm not stupid enough to send my coin to you ;-) ), or do anything to activate this, or will it happen automatically? (If the fork goes ahead, of course).
As stated above, use those wallets that has your private keys and just like the same what happened with the hard fork during bitcoin cash.
For more info about Bitcoin Gold a.k.a Bitcoin GPU try to read it here --
https://bitcointalk.org/index.php?topic=2133536.0