Once you have a hint of inspiration, what do you do with it? 
We're not going to do a standard character sheet. 
There is a place for those, and some people find them to be very helpful, but for our purposes, we are focusing on: What do you NEED to know about your character? 
If we walked into Build-A-Bear and picked up one of the husks of creatures, what do we stuff it with? What needs to be inside? 
 

Do you start with backstory or where your character is now? 

Either way really works. 

We’re going to start off talking about backstory and building a character from there, but you can absolutely reverse-engineer that.
You can either think: I have a character who acts in a certain way because this happened to him in the past, or I have a character who acts a certain way so what could have happened to him in the past to cause that? 

I’ll give examples for both as we move through this.