Hi Glenn
A PM is a personal message - like an e-mail system behind the public front of the forum.
Here's a couple of ways you can PM Pedro - in addition to the one that Paul posted just as I hit the post button for this message!
Click on the "Members" heading on the constant menu at the top of each page of the forum. Then click on "P" and scroll down until you find "Pedro" and click on that. Then you scroll down to the bottom until you see "send this member a personal message" - click on that and start typing your message to him. When finished hit "send message" (you can also save a copy of it by clicking on the little tick box if you want).
Alternatively you can go to the index of the "Real Cars - Members' Photo Album" find Pedro's "El Cheapo Rebuild" thread and click on "Pedro" at the index level - then scroll down until you see "send this member a message" etc etc
If you are in a thread and want to send someone who has posted in there a PM then look under that member's avatar and you will see some little symbols at the bottom on the left hand side. Click on the one that looks like a "speech bubble" and that will take you straight to a PM for you to start typing in.
There are probably a few other ways as well but this will give you a start.
How do you know when you have received and answer or someone has PM'd you? You will see a number in brackets near the "My Messages" Heading at the top of each page - this indicates how many messages you have been sent - all you do is click on this and it will take you to the messages you have received.
Don't worry about being a newbie - you will soon become quite proficient in the ways of communication on the forum. And I hope you find a wagon!
Kathi