You can get plugins to make it easier which will also restore a backup for you.
But if you don't want to do it with a plugin you need to backup 2 things:
1: All the files, pages, images from the server via FTP, can be done when you login to ftp manager from your hosting or using a ftp manager program
2: The MySQL database which you can access via PHPMyAdmin when you login to your hosting
I can help if you pm me.