Can someone explain to me how to use the Bitmap command. I get the bitmap(x,y...    part. X means x and Y means y. But what about the actual map? How should a filled 6x6 sprite look for that command?

But what I'm asking is how should the data look. What would the "rows of that image" look like?

can't you read from Archive with Axe? Or is this because of Bitmap is an OS ROMcall, which isn't fully converted to Axe command (jet)?

If you draw sprites from archive, you will need to follow a few steps.  First have a small reserved place in ram for a very small and very temporary storage such as L5.  Use the copy command to copy the sprite's data to that temporary buffer.  Draw the sprite using that buffer as an argument instead of the file.  You should turn this into a subroutine that does both of these things for you automatically so you only need a single call to draw the sprite.  The exact same procedure should be used with apps as well.  If you're drawing the same sprite multiple times, you can optimize by only copying once and then drawing every instance of that sprite before copying the next sprite to be drawn.