And there is no use to make two threads, just post one and wait for replies. There are always helpful forumers that will help you out

B/ Short form ... AoM works with a mixture of 3-D mesh models overlaid with a 2-D texture. If you want to change a texture .. 1) get a copy of Ykkrosh's AoMed, 2) extract the files from texture2.bar in the Age of Mythology\textures folder, 3) find the texture you want (sometimes this is easy, like infantry g hoplite standard; or not), 4) again using AoMed convert the .ddt texture to a .bmp (bitmap), 5) use Paint, Gimp or other drawing tool to modify it (keeping the same dimensions or multiple of 16), 6) reconvert in to .ddt format using AoMed, 7) put it in the textures folder, 8) Done.

C/ If (B) is too vague, see (A).