Modern Windows PC's use the UEFI Bios. Linux uses the old standard Bios (MBR) You have to boot into Setup (Bios) go to the Boot tab and add CSM/Legacy Boot. Save and Exit, it now should list your USB Flash drive as a Bootable Device.

 

go to the Boot tab and add CSM/Legacy Boot.

BIOS Version/Date LENOVO F5CN40WW, 1/14/2021

Unfortunately, the OP is out of luck in this regard because Lenovo phased out legacy drive support in 2020.

Legacy BIOS Boot Support Removed in Lenovo 2020 products - Lenovo Support US

pcsupport.lenovo.com

 

I don't have that option in my BIOS. I have attached a photo.
thanks

 

Turn the computer on with the Novo Button (One Key Recovery) and select your USB Flash Drive from the Boot menu.

How to Reset your PC to factory defaults - Lenovo Support US

pcsupport.lenovo.com

 

I don't have a novo button. There isn't a novo button on the side or above my keyboard. There is a little hole that only fits probably a pin. Is that it? You just put a pin in there? Is the sharp side of the pin going to mess it up? A paperclip won't fit. I wonder if it will allow me to install Linux Mint alongside Windows.

 

Yes that is it Where can I find the OneKey Recovery (Novo) button on ideapad laptops - Lenovo Support US With the computer off, stick a pin in this hole to start the computer.
If you want to Dual Boot Windows and Linux, and you only have one HDD/SSD then you need to shrink the C: drive partition in Windows Disk Management to leave enough space to install Linux.
Personally, I would first boot the computer with Mint USB Flash drive and choose to Try Mint. You will be able to run Mint from the Flash drive and see how you like it and see if you want to commit to having it on the HDD/SSD or just use it from the Flash.

 

It's been a while now, but IIRC, you press F12 at power on to choose another bootable device. (As has been stated, BIOS/UEFI settings may prevent a USB boot, in which case you need to disable secure boot/enable legacy).

 

@Geekomatic

I did disable Secure Boot in BIOS, and when I tried hitting f12 to enter the boot mode, it displays "Windows Boot manager" and doesn't display my USB drive. I pressed enter to what I thought would be a boot menu, but it just goes right into Windows........The thing is - I created a Windows 10 recovery USB, and when I put in that USB it shows up when I go into the boot manager.

It sounds like you didn't burn the USB Flash drive correctly with Mint, or it too would show in the Boot Menu. Try burning the Mint ISO using Rufus

 

@Geekomatic

It sounds like you didn't burn the USB Flash drive correctly with Mint, or it too would show in the Boot Menu. Try burning the Mint ISO using Rufus

Too many don't try or know how to get the hash.

 

Select the Download Location for your Region Linux Mint 21 "Vanessa" - Linux Mint Review the Installation instructions. Or download the ISO image and burn it to a USB Flash drive with Rufus

 

The ISO may have been mislabeled. It doesn't matter that much. If you want to download the Mint ISO, you can get it here Download Linux Mint 21 - Linux Mint
I would suggest Trying Linux out by running it from the Flash Drive before committing to install it as Dual Boot.