So in last step of my study I learnt you, how to draw simply line.
I do it using a command line. Why? As I said autoCad work in its space.
This space is virtual tree dimension.
So what is mean for you?
When you drawing on card or letter you have only two dimension plate. But If you are engineer sometimes you want to build 3D model of object. In virtual space you can model any kind of surface.
Sometimes you need only plain surface for drawing. Yes you can use for it AutoCad, third dimension will be 0.
But why am I drawinig in 0,0 or 0,100. What is it? When I get 1 measure unit as 1 miliimeter. It simply 1 unit can be different real unit. You can draw in internal units of autoCad, than you can scale your drawing to printing units.
A real printing, can be done in some scales, If you are architect you want to use scales as 1:100 or 1:50, but for detail 1:10 or 1:5 too.
If you are mechanical engineer you want to draw in scales 1:1 ora 2:1 somtimes 5:1. Rather 1:2 scales.
So when you start drawing you can’t decide about what kind of printing scales you will need to. Just draw all in AutoCad units, then decide about printing scale.
It is important to know about printing scale when you set text size. A fonts can be readable so on printing they need to be mimimum 2 milimeters high.
write command text in command line;
Autocad need from you to set start point:
Now set height in AutoCad units, for example 
After that set a angle of text typical 
And write some text [My first text in AutoCad]
and put ENTER key.
As you see , AutoCad write your text “My first text in AutoCad” in position 100,100 units with fonts height 25 unit.
It is a Standard style of text. How to change fonts I will say you in next steps.
To put this text to the paper, on printing form you shold set scale 1:1. And you will get a text with heght 25 mm.
But if you set scale 1:10 you will get a 2,5 mm height text.
As you see drawing in AutoCad is very profesional and precision.
Try to draw simple object with lines and text, and print it in some scales to learn what is virtual space.
That all for this second lesson.