Question about artillery supporting infantry??

[gwtwins]

In the rule book it states that if you can support your infantry with artillery which would give the infantry an attack number of two. I am not really sure how that works. Does one artillery unit support all infantry? if I had 1 artillery and 10 infantry would all 10 have an attack# of 2 or do I need on artillery for eeach infantry. Also I assume I would then move the infantry to the #2 on the battle strip correct??

Lastly,  what are all the letters I keep seeing. Example from a post title (If R1 buys a plane, what do you do G1?) What does that mean?

Thanks you guys have been a great help so far!!

[CptnKeener]

One Artillery supports one infantry
Two artillery support two infantry etc.

Yes, you can then move the supported infantry to #2 on the battle strip

R1 = Russias first turn (R2 = 2nd turn etc.)
G1 = Germany first turn 

Hope that helps!

[Bunnies P Wrath]

If you have 10 infantry and 1 artillery attacking, you have nine rolls of 1, and two rolls of 2.

The 1 rolls are unsupported infantry.
The two 2 rolls belong to an artillery, and a supported infantry, respectively.

If you have 10 infantry and 2 artillery attacking, you have eight rolls of 1 and four rolls of 2.