02 03?
PS: That doesn't sound right to me
in axe you can have PicA7B for example

Look,
http://www.omnimaga.org/index.php?action=articles;sa=view;article=46
He has stuff like
:[0C0C0C0C0100000008090A0000000000000000010C0C0C0C]

In the beginning, he says 0 1 2 3 4 5 6 7 8 9 A B C etc. each represent a tile.

He stores them all to a pic and it seems like
00 is the first
01 is second
02 is third
and it continues like that

So you're trying to store the pics one after the other into a GDB?
...
Technically you don't "store" in a GDB, GDB#, Str#, Pic# etc are just pointers much like L1, except you declare them yourself.
To have the pics after the GDB you can do something like this:
[]→GDB1
[FFFFFFFFFFFFFFFF]
.or [FFFFFFFFFFFFFFFF]→GDB1, it's basically the same thing iirc
[FF818181818181FF]
[0000000000000000]
.etc
and just sub GDB# for the normal Pic#.

Is this what you're trying to do?

So, is there one part in particular you're confused about?

do understand a little bit?

You can have up to 255 choices if you use one byte (two hex chars)

I know how to use one now, but I think there's an easier way for the multiple.
I'll just wait 'till Aetios returns or another experienced person returns.

Hmm, seems that you all have troubles understanding.
So what do the hex numbers in the GDB mean?
Those numbers represent the position of the sprite in pic1 +1
So, if you have 3 sprites, one being +,another an X, and the other an O and they're all stored in a row in pic1, you could get this tilemap: (.. means a blank "tile")

OXXO
+....+
X....X
O++O

This would be represented by this map data:
[03020203]->GDB1
[01000001]
[02000002]
[03010103]

I hope this is more clear.
My point that was not 100% clear to you:
You can store more than one sprite to a pic since a pic is NO MORE than a pointer (which is again just a number)
So have fun storing 15 sprites in a row and play around with it a bit.