Making Textures in a Valve game...

I'm currently trying to make new textures out of scratch for my TF2/SFM map. making the texture itself is simple, but making the normalmap for it... well let's just say it doesn't work. I've tried many files for it, ended with tga, changed the name in the vmt to not have any typos, asked a software online to make a new Nmap
and no matter what I do, even reloading and rerunning the map, the normal still doesn't get used and black and white checkerboard appears. I know the vmt knows he needs a Nmap, but I just can't give it to him.

What did I forget?

right, Orange, I had tried to do that before (forgot to say it, sorry) and Pocket, I used VTFEdit and GIMP.

The Valve Dev Wiki said "tga" but I'm gonna trust you guys.

So I did what you all said, and it seems to work, I don't see any checkerboard. I don't understand why it works now when it didn't before, but I'll say it was me, otherwise the program will kill me. I'm sure it is sentient too.