OK, So I'm building a SS bike for the first time and thought I knew everything until it was time to pick out a chain and then I realized there was this whole area I knew very little about.

I want to use a Sram S300 Single speed crank with a Surly Cassette cog. But when picking a chain I couldn't make sense of all the options.

From Surly: Our cogs will work with 6-9-speed 3/32" chains

Srams website doesn't list the S300 Courier crank but another website said: for 3/32" chains. (Sram's website lists the S300 double as a 10 speed Hard Anodized)

I know that chain links are 1/2" in length and I have heard that 3/32" and 1/8" refer to the width of the chain for geared or track bikes. But I don't know where the 9 sp, 10 sp etc. comes into play.

I am building a single speed bike so 9 or 10 speed doesn't matter to me but I want to know what chain will fit the Sram S300 courier AND a Surly cassette cog.

Anybody know what I'm talking about?
Thanks.