Some very basic questions that are driving me crazy. Pls help

[jamie392]

Here are some of my basic questions:
First off, what is the difference between going range(x).select and range(x).activate, they both become the activecell.

Second,
activeCell.FormulaR1C1= 45 or something, why do we need this formula R1C1 and what does it really mean or do. Without it the program still works?

Third question,
range(activeCell, activeCell.end(x1down)).select
what does x1 down mean, I am assuming that this code selects all code that is present in this block like what you do by pressing shift end and errors. Is that correct.

last question, what does the := do?

Thanks a ton
Jamie