gba and nds roms

im kinda new to the roms thing but can you play a gba game with a flash1 card like dstt or r4 etc ?

No. You need a Slot 2 flashcart device.

i cant convert it or anything?

No. You can package them to play the ROM while it is loaded on the Slot 1 flashcart from the Slot 2, however, you must need a Slot 2 flashcart still to do this method. So you have to get one to play GBA ROMs.