Large Scale Central

Trying to understand track, code numbers etc

Hi, I’m new to this hobby of Garden Railroading. I’m looking for a little help in understanding track and the different code numbers. I’m now just in the reading stage of how to build and design a outdoor garden railway and one of the magazines that I picked up from local hobby store on it’s back page talks about #1 GaugeCode 332 stainless and brass. It also mentions Euro/Narrow Gauge and American Standard Gauge, what is the difference??? For a couple of years now I have had a LGB Christmas starter set running under my Christams Tree, I use the track that came with the set, what is that track called??? I understand that I can use the same track outside, just use a larger radius…Thanks for the Help I sure can use it!!!