Start here, , at the beginning.

There is no program called ‘localhost’. It is the alias for local server access on IP 127.0.0.1 . However, you must be running a server to connect. In your case you’ll need a web server, and possibly an SQL server.

you can learn php by making your PC becomes a web server by installing Apache (or appserv) then you call your own webserver by browsing to

or

It’s not offline, you are still “ONLINE” but online on your own web server. You do edit your php file by notepad directly and the refresh your IE to see what’s changed on the browser.

Yes, of course. you can do all.

For editing offline, I recommend you use XAMPP which is extremely easy to set up - in fact, you just need to run an installer! It is a package that includes the Apache server, PHP and mySQL and other stuff you need.

It turns our comp into a server and so you can test out your PHP files. XAMPP will give you appropriate instructions during and after installation.

Remember that when you are editing offline, don’t use absolute pathnames, otherwise you will need to change all you links when, if, you upload it to a server.

PS As you get more experienced, you will probably want to try and do the installation process by yourself, as it gives you a lot more control.