WordPress runs on a server environment, it’s not an application you install on your computer.
So, first you’ll need a hosting provider, and we have some recommendations at https://wordpress.org/hosting/
Next, install WordPress there either following the guide at https://codex.wordpress.org/Installing_WordPress or using an automated installer in your new hosting account’s control panel (most hosts have this, including the ones we recommend).
Also, I recommend reading through https://codex.wordpress.org/New_To_WordPress_-_Where_to_Start so there are no more surprises. 🙂
If you just want to work on WordPress on your desktop and have a mac you can use ServerPress and it will set it up for you
https://serverpress.com/
Just for the sake of more alternatives, if you are just planning to develop a site locally before taking it live, ServerPress is great, and so are https://local.getflywheel.com/ and http://beta.chassis.io/
Tu run WordPress, you need:
– A web hosting server
– A domain name/subdomain
You first need a domain name or a subdomain. That will give your site an accessible address like http://www.example.com.
Then, you need a web hosting server to host the WordPress files and database. You can get that with about $3-$5 per month.
After you have these two components, you have to connect the domain name to your web hosting account by adding the nameservers addresses given by your web hosting provider to your domain name management panel.
Next, you can install WordPress as per the instructions of James.