About width and height...
A website is usually built with width of 960px; it is some kind of standart, which fits to all kind of resolutions.
While working on layout in Photoshop I always set the document size to 1350x1200px, it gives me more range to work on, but the CONTENT(grid) is 960px. Never work in 960px in photoshop. Once the document is created and filled with content you can increase the height to add more content.
Design a layout from photoshop. Slice it by slicing tool and while saving press ALT + shit + ctrl + S and choose HTML and images both in option. now you can edit the html page manually to create hyper link.
photoshop, the 80s are long dead, and so should be the ideas from them
pixels, my screen is 2600px wide, and is not large
fied size layouts do not work on anything other than the device used to lay them out, even different browsers at the same resolution render fixed sizes differently
slicing images: is long out of date
current best practice is em and %
the course is far out of date, suggest trying a different course,