Hi Alwielland, my advice is that it is better to join Project Management Institute, (PMI), USA to learn more about project management. The objective of PMP is to deliver what client wanted by meeting client requirements. Depending on the industry such as construction, IT, Business etc, there are different techniques to deliver project (Waterfall/Agile/Hybrid).
In construction industry, PMP includes management plan of scope, time, cost, risk, communication, stakeholder, procurement, resources, team, integration etc. Very important part is communication with client, team and stakeholders daily.
There are numerous instructions for this. If you don't have a specific focus, this is a good introduction: https://www.youtube.com/watch?v=qb80N-HfKbk&ab_channel=DavidMcLachlan