I have to say that most people are incredibly bad at using lighting in interior design. Lighting is mood-enhancing, creates environments and much more, and therefore I think that lighting is incredibly important. (Look further down on page 5/25.) A light bulb is not just a light bulb, as there are many different things to think about and the range is huge. But I thought I would give you some simple tips and tricks.
In short, Kelvin is the temperature of the light that the light bulb gives off, see the scale on the left. Lumen is the luminous flux you get from a lamp, ie the strength. This is what you need to keep track of today, and keep in mind that different environments need different lights.