It's common sense... I can't explain to you how to take a leak or why you should. Seeing this kind of thing makes me wonder if you can be trusted to secure your coins... It makes me wonder if crypto adoption is doomed because there's just not excuse for being this deep in it and having no idea what's going on...
The urgency with which I ask you to please RTFM cannot be understated. You'll lose your coins and then blame the crypto, spreading FUD... When in reality, your refusal to get even the first clue is the real problem.
This question and answer scenario has not taught you anything except how to accidentally delete your wallet.dat, which you clearly haven't made a backup of because you didn't even know where it was...
Normally an update is just like "update.exe" that updates everything that is necessary. That's how I updated bitcoin-core just today. It just wasn't my common sense to delete everything and start fresh with new .exe.
Thank you for your concern, but I do know how to make a backup, and I have made a backup several times with different coins. Although I knew where the wallet.dat is located, it can also be backed up through the wallet client, so I don't really have to even find it anywhere. And I have encrypted my wallet, etc.
edit: small edits