If you have any questions don't be afraid to ask. If you look through some of the old contest threads, you will see that we all help each other!!! We are a very friendly and helpful group...you will fit in well!
When I have several choices of the same animal, I pick the one I think is most attractive, realistic, or unique, then check the Download Directory for errors or same .ztd names.
Trial and error is the only way to see what you like. You could check the additional info at DD for warnings or errors. Lots of the ZA animals have problems. I was more interested in fixing scenery first. If you can't find it at DD just ask me.