1. CUTTING THE DESIGNS TO HTML
When you first see the design of your website it will probably be in the form of a graphic, like a JPEG. However, at this point, it’s just a picture and needs to be programmed or ‘cut’ into HTML in order for it to become a functioning web page. That process begins with the designer handing over to the programmer a PSD  file. These are the ‘source’ or original files which contain all the design formatting, graphics, fonts, text and style guidelines .
The PSD is then carved up into individual elements and coded so that it behaves like a normal web page (although it won’t actually do much at this stage until the CMS has been added). It’s also the point at which the mobile version of the design is coded. Often this will look different to the standard desktop version of the website because of the constraints of screen size. For example, you’re likely to see the ‘hamburger’ (three stripes) instead of a menu or you might find the page’s content stacked in one column rather spread out or find that actual content is changed because of its appropriateness to a mobile browsing experience.
The PSD is then carved up into individual elements and coded so that it behaves like a normal web page
Next, we make sure that the web page looks the same for different browsers (and different versions of the same browser) . This is known as browser compatibility and can take quite some time to get right.
This is also the point where your accessibility (high visibility, dyslexia, no graphics, etc.) styles are created and browser tested.
2. BUILDING THE CONTENT MANAGEMENT SYSTEM
Now for the ultra-techy bit. Our programmers usually geek-out because this is where all the functionality defined in your specification gets turned into your Content Management System. In reality what we’re doing is customising an existing ‘engine’ (in our case that’s Proteus but it could WordPress, Magento, etc.). The extent of the customisation is dependent on the nature and number of functionality requests you’ve made that isn’t already covered by the basic engine. Unsurprisingly this, to a large degree, determines how long the coding element of the project will take.
At the end of this process, you (in theory) should be able to enter content into your CMS. However, we don’t recommend this for two reasons;
- you won’t be able to see your content appear on the front-end of your web site making it quite difficult to judge whether you’re entering anything sensible and;
- any changes to the system could affect (and possibly destroy) your content.
3. INTEGRATING THE HTML WITH THE CONTENT MANAGEMENT SYSTEM
Once the CMS is complete it needs to be integrated with the HTML. Think of this as linking the back-end (the CMS) with the front-end (the HTML). Essentially this involves attaching a database to the HTML giving you the ability to edit/add pages and content into the CMS and see them appear as a website or websites.
Once this is done you should be in a position to test your new website!
 A PSD file is a file generated by a product called Photoshop and is extremely popular with designers. There is other software which designers use, InDesign being one, Adobe Illustrator another, but on the whole, Photoshop is the industry standard.
 Zamzar is a useful little online tool if you are trying to view PSD files. This website will convert one file format into another so you can turn your PSD file into a JPEG.
 The typical browsers most web design companies work to are; Chrome, Internet Explorer/Edge, Firefox, Opera but here's a more complete list from Clicky which includes how many people use what make and version of the browser.