This question is very vague, so allow me to be more specific:
I divided my USB drive (a temporary storage device until I get an SSD) into 6 partitions using GParted. I planned to use Rufus to install multiple Linux distros (up to 6), but I forgot that it actually identifies the whole USB drive, not individual partitions. The partition table is formatted as GPT, and each partition is ext4.
I also don't know how that would work, since wouldn't the GRUB boot loader install on each partition? Would this cause any flaws? Should I make a partition containing only GRUB?
I am still learning the concepts of Linux OSes so I'll be at a slow pace. My main goal is to be able to boot up any OS of Linux I have installed by choosing it in the GRUB or something of the sort.