You can use Rufus or BalenaEtcher (my preferred version, both good).
To make an install 'disk you must first download the Mint ISO file and store it somewhere you can find it.
Plug in a USB stick or pop a DVD in the writer.
Start the software to create your bootable stick/disc. Usually it will first ask for the location of the ISO file, then it will confirm where you want it written. There will be a warning pop up telling you that the volume will be erased - TAKE THIS SERIOUSLY and check you're not overwriting a fixed drive.
Click on the 'go' button and it will take just a couple of minutes.
To try your 'live' OS, restart your computer and tap the F12 key as it starts to post, before the OS boots. It will ask you which drive you wish to boot from, and you should select the one with new OS installed.
Easy.
BTW for those trying different distros, I've recently tried CachyOS - based on Arch linux, this runs very fast even with a heavier desktop like KDE Plasma installed. Booting from an SSD plugged in through a USB port takes 20sec on 10 year old mid-spec hardware, and the system is very responsive when running.