LibreCAD - Failed at First Hurdle

I'm coming from a CorelDraw background which was so simple.

I've rough drawn a box about 120 x 150mm and put the measurements on each side.  So 3 objects/entities??
I now want to change the box to the accurate measurements.  Right click on box line and expect properties box to appear with dimensions X and Y, line thickness, colours, fills etc etc.
Nothing.
Find Modify.  Still not a lot.
Change box corner position.  Measurements don't change with it.
So still searching for a simple, intuitive CAD programme.
Shame.

If you look to a simple tool for simple "drawing" -> LibreOffice Draw.
If you look for complex tool with parametric design (I change one dimension and everything is updated) -> FreeCAD.

To achieve this with LibreCAD needs drafting in a similar way as hand drafting:
1/ Draw a new box with the correct measurements
2/ Create the dimensions to show the measurements;
Video tutorial should be able to teach you this quite efficiently.

But I do not know any intuitive software so you probably want to try hand drafting (this is intuitive and fast at least for simple design).

Draw the box exact from the start.  Here are three (3) ways to the same box:
 
OPTIONS ==> Current Drawing Preferences ==> Paper, Units, Grid, etc.

LINE ==> 2 Points
Specify first point
0,0
Specify next point
120,0
Specify next point
120,150
Specify next point
0,150
Specify next point
0,0
 
Or

LINE ==> 2 Points
Specify first point
0,0
Specify next point
@120<0
Specify next point
@150<90
Specify next point
@150<180
Specify next point
0,0

Or

LINE ==> RECTANGLE
Specify first corner
0,0
Specify second corner
120,150

It is now exact.  Aligned Dimensions will confirm.
Done

Thanks.  Uninstalled and gone back to Draw in LibreOffice,  where object properties appear when an object is selected and are all very easy to text edit.
I'm just amazed that there doesn't appear to be right click context menus either.