I am new to bitcoin and I just bought 0.12 btc few days ago from localbitcoins and I use electrum mobile wallet to keep my Bitcoin.

What exactly is fork? Or Hard fork?

I heard that those who own bitcoins before 25th Oct will receive Bitcoin Gold. How does it actually work? Do I receive Bitcoin Gold automatically in my electrum wallet or do I need to do it manually?

And if I have 0.12 btc how much would I receive in bitcoin gold? And does the value of my btc change ?