Asked
— Edited

how do i ad a male or female connector to my design.
and second ,how can i see or ad size to it.
how do i ad a male or female connector to my design.
and second ,how can i see or ad size to it.
As for changing them any, you would have to edit the .stl files in a 3d modeling program.
ok then .are there any free downloads,3d programs?
I highly recomending some you tube vids on Blender tutorials. Also if you have no experience with 3d modeling, you may want to get 123d design or sketchup to get familiar with the basic tools. They are more user friendly and help you figure out Blender.
In the end you're going to need blender to modify the existing stl files. you can try remaking them from scratch with 123 or sketchup and then export them to stl. I use 123d when I can.
123 has stl export native to it. sketchup requires a plug-in to export stl files. I personally had issues importing the sketchup stls into the EZ Bit designer and switched to 123 because of that.
I only use blender to edit existing stl files. If i'm strarting from scratch I'll make up most of what I'm doing in 123d design and then import the stl into blender if I have to.
I hope this info helps you out.
thank you