I'm not using a Droid 3, so please bear with me, as the placement of some things may be a little different for you.
1. Touch and hold a blank area of your homescreen. A menu should pop up that will allow you to create a folder. Once you create this folder, go to it on your homescreen and tap it. Once it opens, touch and hold the title bar to rename it . I will use Games as an example. Then touch and hold the games' icons that you wish to add to this folder and drag them into the folder. Finally, touch and hold, then drag the folder icon to where you want it on your homescreen.
2. You can't delete a stock app on your phone (without modification). If it is on your homescreen, you can remove it by touching and holding, then dragging it to the trash can that appears at either the top or bottom (most likely) of your screen. The other app is for any other email account that is not GMail, such as Exchange mail.
3. No, this shouldn't prevent you from receiving phone calls. Are you in a low signal area when this happens?
4. Both Widgets and app icons can be on the home page. Widgets are shortcuts to the information that the app contains. An example is a weather widget that gives you current conditions on the homescreen, without having to open the app. By contrast, an app icon is only a shortcut that you can tap to open the full app. Think of widgets as being dynamic windows into an app, vs. app icons are static doors into an app.
I hope that this helps!
