erase, wipe macbook pro

thank you leroydouglas, your reply was helpful, I succeeded in wiping the MacBook pro, however apparently managed to delete the OS as well, rather than just my personal data and files.

I have gotten to internet retrieval which leads to Mac OS Lion, which guess is original software when machine was new. However, when I get to install on Mac HD, get msg, 'can't download additional components to install Mac OS X'

when I click on 'restore from time machine backup' get box asking for disk containing time machine backup. I have Seagate external drive, believe can retrieve the older MacBook pro data?

So am i on right track, or do you have additional suggestions?

Thank you!