Qualifications-based selection is a way of choosing people or companies to do a job based on what they can do, rather than just looking at how much they cost or who they know. It's kind of like picking your favorite crayon color to color a picture, but instead of picking the prettiest color, you pick the crayon that is best at coloring in the lines.
For example, if someone wants to build a tower, they might ask different companies to show what they can do and how good they are at building towers. Then they would pick the company that has the most experience and expertise in building towers, rather than just picking the company that charges the least amount of money.
This is important because if you pick the right person or company for the job, you're more likely to get a job that is done well and will last a long time. It's like picking the right tool for the job – you wouldn't use a hammer to put in a screw, because a screwdriver would do the job much better. So, by picking the right person or company with the best skills and experience, you'll get a job that is done the right way the first time.