What is, how do I get and how do I use a flat texture file?! ( help me please!)

I'm not entirely sure what you mean, could you please give us some more details on what you mean so someone could help?

I'm try 2 ask about how to get and use a flat texture file

Flat texture file as in Floor texture?
If that's what you mean then You have to buy the item and create a picture for it depending on what size you bought the Image would have to fit into that size or would be resized.

If that's not what you meant then i don't know what you mean.

First, you need to buy a head texture item. The cheapest one is 128x128 head texture and it's price is 2000 tc (you can get cheaper in market).

Once you buy that item, it will allow you to use flat texture files. Go to your inventory and look for your texture item. Now click on "edit" and then click on "upload file" then browse for your flat texture file and upload it.

You are done! the texture shall appear ingame after some minutes.

Also, there are other head texture item sizes: 128x128, 256x256, and the coolest one, 512x512.

Here is a method explained for using flat texture without buying the time:

http://forum.toribash.com/showthread.php?t=28309

But the downside to this is that in multiplayer, other people won't be able to see it.

Oh, I missed where he said File, Yeah just to add on to what Akmal said.

You can add a texture file to any part of your tori's body after you have bought the texture item for the certain part, But the file as you are talking about is user created to personalise your tori so you can either make one or pay someone else to make one.

In case you're talking about a flat image file, that means there's only one layer in the image (no alpha/transparency).