Animate signing a signature...

Hey!! I'm Lisa. I have only begun learning about SVG and in the last couple of days, I have learned quite a bit, but still shaky on the details.
 

 I found this CodePen for animate signing of signature with an SVG and the problem is, how do I get my SVG graphic to be only a stroke and not an outline. Tried to reach out to the guy that wrote it but it looks like he's had no activity in about a year, on his GitHub anyway. I was hoping maybe someone could break it down for me in a 1-2-3 kind of way. I tried just substituting my paths but it didn't work.
 

 Is it possible to 'fill' a path in a linear fashion? Where it fills from point a to point b over a period of time? And the stroke would be 0. Does that make sense?
 

 I sure do appreciate any help or an alternative method. 
 

 Thank you!