Welcome to the forums
I have installed many duel boots for various friends & family over the years, here is my basic guide to installing Linux,
Also be aware that Windows updates can break the Linux boot grub [search windows broke my Linux for guidance]
What do I need?
Depending on the age of your machine you will need an installation medium, this is usually a clean pen-drive of 4gb minimum [try not to exceed 16gb], make sure it is of good quality and formatted to FATS,
On older machines that are not USB bootable, you will need a clean New DVD-r,
Make your ISO installation medium [pen-drive or DVD-r]
1] choose your distribution and go to the Official download page
2] on the download page you will find an SHA sum, make a note of it
3]download your chosen distribution
4]burn a bootable installation medium.
For a USB pen-drive to do this, we recommend
https://linux-tips.us/balenaetcher-a-tool-to-turn-linux-iso-files-into-bootable-usb-drives/, Or for optical disc, select burn as ISO image in your burning software
5]Which ever you use, now is the time to check the SHA sum [if you are unsure how, then see this article
https://www.linuxshelltips.com/verify-sha256-checksum-of-file-in-linux/]
To Install
For best results, ensure your computer is either hard-wired to your router, or has a Wi-Fi card installed
1] Connect the computer to mains power
2] Insert USB into drive [or optical disc into drive]
3] Switch on and open the short boot menu [method will depend on the make and model of your computer]
look down the list and find USB [or Optical drive]click on it and enter, after a few seconds [depending on your choice of distribution] it will load a “live” session to Ram, [you do not need a hard-drive installed at this stage if you only wish to check Linux will work on your machine]
4] When it is loaded your desktop will appear, now is the time to check everything works OK, [Wi-Fi, sound, & graphics], the easiest way to do this is click on the wireless icon find your router and enter the password, when loaded go to your favourite music video site and pick something you are familiar with, if it plays OK and the picture looks good, and the sound works you can then decide if you wish to continue the installation.
5] To start full installation, double-click the installation button on the desktop. The ISO will then check the components of your machine this may take several seconds to a couple of minutes, then provided the hardware checks out OK it will start to install
6] Watch it install when it asks about partitioning this is your final chance to decide if you want to dual boot with your existing system [select installation alongside]or wipe the system and just install Linux [select use complete drive], choose your option, and enter
7] During install most distributions will ask if you wish to install non-free/proprietary drivers tick the box for yes and enter [non-free does not mean it will cost you to use ,just that it is supplied and licensed by the manufacture]
8] You will need to enter information as it installs so keep an eye on it, a typical Linux installation can take from 10 to 20 minutes [far less than windows]
9] When it has installed you will get a message do you wish to re-start now, accept and enter [remove install medium when prompted]
Now sit back whilst it re-boots, then it will take a couple more minutes to clean up the installation and get rid of the installation files,
Then if all goes well we will have a working Linux box
Now open the update manager and run a full update,
When you have successfully installed your Linux distribution, we strongly recommend you install and activate “Timeshift” [this is similar to windows restore]
Being new to Linux, Please accept you will need to go through a brief learning curve,
Bwiz
Addendum, you can download and run as most distributions to try them out live, they won't install until you tell it to [ 5 above]