I am working as a Software Test Engineer, recently i had a offer from a small company and my work is to design a whole Plan and functional test case problem is that there is no documents which will help me to figure out the application behavior.
In that condition from where should i start...?
You can start with hand on practical experience with the application itself or you can go for some brain storming sessions with other stake holders like project manager & developers etc. and then you can start preparing your own documentation.This process can go ahead iteratively all you need is cooperation from other members.(hope it will work for you)