hi i need help to add more textures to the editor
can someone help me?

just click on a white texture field in the editor and browse for your texture (PNG-format).

Well, first of all its double click.
But you need to have your textures in the data>bitmaps>textures folder.
The texture must be square of 2 dimensions (2 4 8 16 32 64 128 256 512 1024 2046), but it doesn't have to be square.
Don't they also have to be 32-bit color?