Creating custom gym badges?

Hey guys! I'm new to the community and was wondering how to make custom gym badges ontop of the existing badges? so instead of having 8 badges I want to be able to have 16 and then eventually 24 badges all up, I am creating area's for the post game of pokemon leaf green so that people are able to obtain the other 2 regions
Thanks for the help guys!

Badges are literally flags. so there is not much mysteries about flags. If your question is about showing those in the TC and the continue menu, well, that's another thing that might require ASM hacking that i have no idea about.

Yeah I don't mind about it not showing up just need a guard to check the flags and the gym leader to set the flag to true, I'm not 100% sure how to do this? Could you please give me some more insight, thanks In advance! :)

Since you're trying to add extra badges on FR/LG, just open up a gym leader's script and you can see how its done. In Brock's script you'll see the command 'setflag 0x820' on line 19. Whenever the game wants to check that you've beaten Brock, it will check if flag 0x820 has been set or not. Have a look at diegoisawesome's XSE tutorial as it goes over how to use flags when scripting. For your extra gyms, you will just need to use a flag that isn't used anywhere else in the game - Here's a list of flags that are used in-game in this thread. There aren't many of them so you'll need to use them wisely.

I'd also strongly recommend that you switch over to hacking FR, instead LG. While they might seem to be the same game on the surface, a lot of their internal data is in different locations, making it incompatible with most tools. You will have a far easier time in terms of tool compatibility as well as things like ASM as almost everything on this forum is tailored towards FR.

Thanks heaps for the information! and OK might try to re-create my rom in fire-red, I'm not heavily modifying my rom, It's more of a rom for just a friend and I to play on!

this has been very helpful thanks :)

EDIT: I am a little bit confused sorry guys, but when he says that these free flags are between 200-2FF does that mean like 200 decimal or hexdeciaml? :l
Was unsure on how to explain what I meant!

Hexadecimal.

Awesome, thanks!