Hey Mark, welcome! Characters are a bit more complicated, so my suggestion would be to just start with making a character in general first and worry about realism later. These courses will help:
https://cgcookie.com/course/introduction-to-character-modeling
https://cgcookie.com/course/sculpting-the-wrangler
https://cgcookie.com/course/art-of-sculpting
https://cgcookie.com/course/modeling-realistic-characters-with-blender
At this point I would suggest you sculpt and model your characters from scratch for each new project, until it becomes so easy for you that it becomes tedious. If you need a quick result to start (or want to focus more on learning about making environments first) you can definitely use Daz or Poser, but in the long run they become creative crutches if relied on too heavily.
Hope that helps!
