help extracting rar files become .gba

i am new at this so please forgive any ignorance. i have downloaded a game for nds and have followed instructions to extract rar files but i end up with a gba file. what am i doing wrong?

What NDS games are you downloading?There is no real way to extract it to a GBA file if it was meant to be a NDS file.

have downloaded a couple of spongebob games for my kids. the first one worked ok but froze whenever the kids started to play it and the other one kept doing the gba thing

Are you using a slot-1 flash card?
you need a special GBA adapter to download and play .gba games.
please tll which card you are using.

...I believe you downloaded a gba game by mistake.So the file extension when extracted is from game.rar to game.gba?Or is the extracted game's file icon look like a gba-if that's the case that's the way the options on your pc are......as for the errors, what flashcard are you using-as in brand.Just what the label says is fine.