Drawing dimensions is an art that can be learned very easily. Here is a video tutorial on how to drawing dimensions oriented in different directions as like 2D and others like that. There are a lot of shapes that can be drawn step by step following the video tutorial.
Start your drawing with 2D then try 3D, after getting mastery into this you can try further to have drawing on 4D 5D or even 6D.
How to draw Different Dimensions including 3D
Follow the video tutorial and then you will easily be familiar with how to draw 3d dimension or any others like that.
Concept of dimensions:
Concept of dimensions can easily be understand. Just think it like directions. For example 2d in just xy axis and 3d in xyz axis.