Unity has three different main render pipelines at the moment. HDRP, URP, and the legacy render pipeline. The high definition render pipeline (HDRP) is best suited for high fidelity applications with global illumination and volumetrics whilst the universal render pipeline (URP), formerly known as the light weight render pipeline, is more suited for lighter weight applications with its options for simplified lighting, shader variants, and GPU instancing. You can select templates for any of these from the project creation menu in the Unity Hub.
Installing Unity
First head over to https://unity.com/download and get the Unity hub. In this case, since I'm using Windows, I will be downloading the Windows setup. After the download is complete, run the executable file and follow the setup instructions. During the setup process, make sure to make a Unity account or sign in with google. Depending on your selection during the download, you will either get the Personal (free) licence or be prompted to enter your licence key for Plus/Pro edition. Once this is done head over to the install tab and select a version, the best practice here is to just install whatever one unity recommends which is usually going to be the latest LTS version. This long term support version will get the most updates and likely be the most stable. Finally when installing make sure to select windows build support and universal windows platform support. This will make sure you can build your project for windows pcs (these can always be changed later). If you wish to build for other platforms such as android for mobile games make sure to select them too!
Making your project
For this tutorial I will be covering the URP and HDRP options as Unity has transitioned away from using the Legacy render pipeline. To make a project in these versions first open the Unity Hub and click the create project button, here you will be able to select the template you want to use. I will be using the 3D HDRP template. Once you've selected this Unity will begin creating your project (this may take a while) once Unity finishes loading the scene congrats! You've got a Unity project.
Where from here?
From here there's a few things you can do. If this is going to be a project that you work on frequently and want to keep backed up id recommend using GitHub, you can follow the other tutorial which I made here for that https://alfiedev.co.uk/how-to-use-github-with-unity/ If this is your first time using Unity id recommend checking out my other tutorials or keeping an eye on this site for when they come out as I will be doing a full series making a game start to end, another good place to start with tutorials is the youtube channel Brackeys, however some of his tutorials are very outdated now and you will run into occasional issues with them.
Since you're now a Unity developer there's a few things you will want to know about when it comes to solving issues. Firstly the Unity documentation is wonderful and can be accessed using the link below. Other useful platforms are the Brackeys and official Unity discord, the Blender discord, stack overflow, and reddit. Most problems can usually be solved just by searching them on your chosen web browser, and putting Unity on the end. E.g “How to raycast Unity”
Useful Links
Youtube channels-
Brackeys - https://www.youtube.com/@Brackeys (general Unity tutorials)
Gabriel Aguiar Prod - https://www.youtube.com/@GabrielAguiarProd (game vfx like shaders and muzzle flashes)
Discord servers-
Brackeys Discord - https://discord.gg/brackeys
Unity Discord - https://discord.gg/unity
Blender Discord - https://discord.gg/blender
Other sites-
Unity Docs - https://docs.unity3d.com/ScriptReference/
Stack Overflow - https://stackoverflow.com/
Unity Reddit - https://www.reddit.com/r/Unity3D/
I have no affiliation with any of these sites, platforms, or channels. They all just really helped me out whilst learning to use unity and might help you too!