How to recover my lost data?

How may I recover deleted/corrupted ‘documents’ that I had on my MacBook Pro (OS X 10.8.5 currently)? I transfered much data and deleted some valuable ‘documents’. Well, after forgetting some pass codes, I now want to recover the lost data; at least of those more valuable documents.

I want easy-to-follow instructions please. Please tell what website to go to for some free recovery software or how to put in some command(s). Please help.

RFO

Time Machine would only help you in the future. Is your Mac set up with Time Machine? If so you should be able to get the deleted files that way. Click the Time Machine icon in the dock. Then go back to before you deleted the files, they are probably still available.
If you don’t have a Time Machine backup yet,
Maybe you can try uFlysoft Data Recovery for Mac, it can recover data on Mac only in three steps:

Step 1. Launch the software to scan the device where your files deleted

Step 2: Preview the scan result files and make mark if it is the one you find

Step 3: Recover files