login and password for new install

i have been fighting a raspberry pi 4 for a month. there links and downloads are broken, and dont seem to get me any where! i was so happy i found "rufus", (no thanks to them) and a debain OS that booted up and worked ! but i was sad to find my self not knowing the login and password ---(20200831_raspi_4.img.xz)and this (sha256) <---- might help someone help me i dont know what that all means but its what the image named its self when it downloaded, ANY help would be golden! :-)