This is the official Linux Mint installation guide: https://linuxmint-installation-guide.readthedocs.io/

Are there step by step instruction available?

You may very well need specific instructions to convince your motherboard to boot to the Linux live USB media.

Although, if you replace the Windows harddrive with a blank harddrive, many motherboards will then do the right thing and boot to the Linux live USB key.

(Warning: Get your files off the Windows drive first. The windows drive is probably encrypted, and so won’t be useful for recovering files later.)

Getting booted into the Linux live media is by far the hardest part.

Once you’re booted into the Linux Mint Live USB key, make sure Linux Mint detected and is able to get on the Internet. You’ll need your wifi password.

Once you’re happy with that, click “Install Linux Mint” and just follow the prompts. The hardest question for me was remembering what my time zone is.

Linux Mint will tell you when to reboot, and will even remind you to remove the Live Media USB key.

Reboot and enjoy Linux.

Getting a modern motherboard to boot to a USB key is still a royal pain in the ass.

Pro tip: if you have the luxury of a spare hard drive, use it. Pull the old windows drive out entirely and set it aside to pull backups from later. Various “security features” that work to “protect” your Windows install behave better once the Windows drive is completely removed.

Once the Linux live USB is up, just click install and then “next” a bunch of times.

Pretty straightforward actually, plenty of distros even ship their own USB flasher tool so that you don’t have to use rufus.

Definitely step by step instructions available and even official videos now.