I occasionally get ask how one could get started with Linux. This shall be a short reference that can guide the way to use Linux as a main operating system, if wanted. I will assume that you have no or only negligible experience with Linux. Then I also assume that you have a computer which runs Windows or macOS.
Virtualization and easy Distribution
If you want to try Linux, the best way is virtualization. For this you install a program which simulates a virtual computer which then can run Linux. If you have a processor with virtualization support, the virtual machine will run almost as fast as your native operating system (Windows or macOS). The hard drive of the virtual machine will be just a file on your computer. If you don't want it any more, you can just delete it. It will also not break your original operating system. Therefore this way is best if you do not want any permanent changes.
A free virtualization software is VirtualBox. You have to download and install this software.
Then you need to download a Linux distribution to install. There are many to choose from, all have their advantages and disadvantages. In every case there is an ISO file you can download and install in the virtual machine.
You can have a look into my opinions about Linux distributions. A very popular choice for new Linux users is Ubuntu. Go to the download page and get the ISO file. If you are not sure, you want to have the LTS (long term support) variant. If you computer is made after around 2008, you should use the 64-Bit version.
My current distribution, Fedora, would also be a good choice for a virtual machine if do not need multimedia.
With a virtual machine, you could also try out both.
If you have downloaded both, the steps are roughly these:
Install VirtualBox, just follow the installer instructions.
Create a new virtual machine and say that it should run Linux.
Before starting the machine, you should edit its properties. It is recommended to increase the memory to be between 2048 MB and half of your machine's memory. Set the number of CPU cores to 2 and increase the video memory in a different tab.
Start the virtual machine. It will ask for a CD/DVD to be inserted. Point it to the ISO file with the Linux. The machine will then boot from the DVD.
Select something like "Install". Then go through the steps in the installer. The Ubuntu one is straightforward. The Fedora installer is a bit cumbersome to use. In either case, choose "use full disk" although that sounds scary. The Linux installer refers to the hard disk in the virtual machine, and you want to use that fully.
Let it reboot, then you have a virtual Linux running.
One can repartition the system such that Windows and Linux, or macOS and Linux, can be chosen at boot time.
There are disadvantages:
You have to reboot when you want to switch between the systems.
All your hardware needs to be supported from Linux, sometimes that is a problem.
The Linux installer is sometimes not capable of resizing the existing operating system. Then you have to reinstall the original operating system which usually is an afternoon of work, if you know what you are doing. In the worst case you make your system unusable in the process.
The advantage is that only one operating system is running at the time and you can use all the performance of the hardware.