If you are developing a website then you may wish to sue WordPress. It is very popular amongst beginners and fully fledged web developers sue to its flexibility and easy to use content management system. Once you have installed WordPress on a website you can then start to personalise it. It does come with a few themes installed but these may not be sufficient for what you need.
When looking for a theme to use you need to do plenty of research. Read reviews and look at demos of a live site that uses the theme to see if it is right for you. If you are going to have to pay for then theme then be sure to get in touch with the developers of it to ask any questions you may have before you make the purchase. Checking things such as, how many menus it supports and if it is compatible with other devices is a must.
Plugins can be added in to many themes to allow for additional functionality. This may be to add a sign up form to your site or to put in a scrolling picture gallery. Again you need to check carefully what the plugin offers and if it is right for you. You may be able to see a working demo of it. Always back up your site before changing the theme or adding plugins.