How in laymans terms do I restore a .dat BTC backed up wallet file on my mac please? the bitcoin wallet backup.dat file is in my documents
but I'm not an advanced computer user
I have the complete bitcoin qt on my computer but don't know how to restore from the backup
Close Bitcoin core so that the program is not running. 
Go to /Users/{yourusername}/Library/Application Support/Bitcoin/ and there you will see much of the blockchain data, and a wallet.dat file. 
If there is a wallet.dat file here that you also need, save it elsewhere by copying and pasting.
Put your backup.dat in this directory, and rename it to wallet.dat.
Start Bitcoin-QT with the -rescan option so that it will go and look for any coins that your received in the blockchain.


That's it!