For these advanced tests, there are many ways for you to know "how" and "why"
1. Go to check their corresponding ASTM D-xxxx articles and read through. It gives you the first impression of "how", and sometimes "why" we do this way in the industry.
2. There is a set of Soil Laboratory Manuals authored by Head, it provides a lot of details so much so that you will be an expert one day after you learned "whys".
3. Check out Master and/or PhD thesis that covers a test topic that you are interested in. It will also inspire you to explore some improvement techniques if you are aiming at that direction.

Of course, you should always have some hands on experience with basic training in a sound geotechnical laboratory, before attempting any advanced testing technique for the sake of your resource and efficiency.