Yeah, the most popular tool is world machine followed by world creator so many people do tutorials for them. The official documentation should be completed for this month I believe. Although Gaea is quiete intuitive coming from world machine so in my case I didn't feel the need to follow tutorials to learn it but the…
ive reported the bug on their support system on their site. I will shoot them an email soon as well. About the Erosion studio, theres not option as far as i can see for importing. It kinda sucks that theres only one or 2 guys doing tutorials for Gaea right now.