I haven’t had a lucid dream yet, but once I do, the first thing I want to do is talk to my spirit guide. How could I do so? Is it as simple as looking up into the dream sky and asking to see my spirit guide? Also what is my spirit guide. Is it something random, or something I have always though my spirit guide to be?
Welcome Picknick10! 
Why don’t you introduce yourself to the whole community in the Hi, I’m new here topic? 
The methods to meet your own spirit guide tends to vary, however one way that could work would just expect hir just around the corner, or just ask someone for directions.
As for the appearance, it tends to be a surprise for most (if welcomed), and I’m sure you don’t want yours to be spoiled 