If you press Control while moving objects, you’ll move them in “grid units”, that is to say, it’ll move in steps equal to the smaller grid square you can see, but it will not “align” to the grid. If you want a vertex to be aligned to the grid, you have to press Ctrl-S, and choose “selection grid” from the menu that pops up.
Sorry, you lost me there.
Yes. If you press N you’ll get the Transform Properties window. In object mode, it tells you the size of your object. Also, when in Edit Mode, go to the the Editing Buttons(press F9 to see them if you get lost, it on the Buttons Window), to the far right, there’s a lot toggles that turn on, among other things, display of normals, of edge length, of face area, etc.
hope this helps