I have written openSUSE tumbleweed.iso into USB but I dunno how to install it from USB. I am using gnome/fedora.
You want to install another Linux distro onto your computer? Is it what you want to do? Insert the USB stick to your computer, reboot and then hit the keyboard key that give you the boot menu. (On mine it’s F8).
When you say you written the .iso to the USB stick - which app did you use?
Yes, i want install another distro on laptop. I have written .iso by fedora media writer. After I reboot, the computer goes straight to fedora and I don’t see opensuse.
When you see the brand of your computer on the screen (the first thing you see when you turn on your computer), you need to tap the boot menu key like a maniac. If you don’t know which key is your boot menu key, you can go into BIOS to find out.
Find the manual to your computer, it should properly tell you what key it is.
F12 at BIOS start should get you into the boot menu.
My system with an asus motherboard gives me a bios splash screen while booting with the instructions to press
Del to open the setup menu and
F8 for the bios boot menu.
Booting from the usb would be done the same way it was done when you first installed fedora. Use the bios boot menu in most cases.