I have been working with nixOS for a bit of time now and I want to move to debian, I already have the ISO file and it is already flashed to my hard drive. The only thing I am having trouble with is entering the boot menu, similar to how windows has the recovery mode where you can boot from a usb. I did not dual boot windows not realising this would come to bite back another day….

if yall could help me it would be great

Im rlly stuck and i dont really know what to do right now… I tried surfing the web but nobody provides tutorials for this.