which selection filter must be set before using 2D selection?
Here is a web series that could be of use, it will take you through a step-by-step guide.
Also, I would suggest resources such as google and youtube to be amazing forms of teaching in some aspects. If you are a visual learner it is possible to find many many guides out there on the internet that could be of some use.
Let me know what it is you are specifically looking to learn and I will post some links..