Hi @edstore welcome to the /e/ community.
I am going to point you to Know your hardware - Samsung where it is explained that the “Downloading, Do not turn off target” is static. It means “Ready” when you first see it.
Once you have introduced the new Recovery , the message stays exactly the same! Actually now “Ready” for you to reboot it into Recovery mode, when you are told on the PC that the flashing was successful.
So do not worry about what is showing on the device, at this point you take you lead from the PC, and reboot when told to by Easy Installer. Have a quick read of that article as there is a timing issue that you need to get right at this point. (You may notice that in the little video there, the phone is showing just your screen as he starts to boot into Recovery mode - TWRP is a branded Recovery, Easy Installer may supply /e/ Recovery today.)
Do not hesitate to ask again if needed!
Bon chance