USB HDD Not booting PLEASE HELP

I have an Acer Nitro 5 AN515-51 and I've been trying to get Catalina to work on my pc. Alas, when I go into my bios, the drive containing Catalina shows up, but after moving it above my regular windows boot drive, It always boots into windows 10. I've also tried with Mojave to no avail. Is it because of the computer im trying to use it on? Or is there some hidden step I have to make to make it work correctly.

submitted by /u/Niceyner
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