Making a custom fps character in blueprint?

I know that there is a pre existing fps template available but I’m trying to learn how a fps character would be set up from scratch in Unreal’s blueprint system. I’m a bit confused as to where I should start and I need some suggestions.

I am not completly sure what you mean. Do you mean to set up an enterily new Blueprint or using the existing character blueprint and changing the mesh? I recommend you to just change the mesh of the existing and active Character Blueprint, because
theres already that movement and look stuff. Otherwise, you would need to take a look on that movement, look, and shoot functions.
Take a look at this: Setting Up a Character | Unreal Engine Documentation
And another good tutorial series from Epic Games: 3rd Person Game with Blueprints (pre. v4.8) - YouTube (its 3rd person, but you can do everything except the camera position exactly the same).

no truer words have been spoken lol ^^:(