General scale is for the scale, for 1/4"=1'-0" you set 48.
Is this done under drawing preferences? Where do you set it to "48"?
48 is not in the drop-down list, you have to type it in manually.
In Print Preview set your scale (1:48).
Where is this set in print preview? Could not find a way to do this.
Again, 1:48 is not in the drop-down list, you have to type it in manually.
The size of letters etc. can then be set in real on paper size.
This is set to 1?
This refers to text height, arrow size and other things in dimensions. So if you are in inches, you might want a text height of 0.1 inches, near to 2.5 mm on paper, which is standard for normal text.
If you use a frame, it has to be drawn 48 times the size.
A frame is a physical sheet I have drawn in Libre? So scale it up 48 times?
If you want a frame of 24x36 inches, like your paper sheet size, you have to draw it 48 times larger, 1152x1728 inches, because when printed it's scaled down again.
That "General Scale" thing only works on dimensions.
Try out the sample drawing I have attached and study the settings in "Current Drawing Preferences".
The inner rectangle with the dimensions is just a symbol for maybe a ground plan.
Also study the manual I have added a link for. It is quite comprehensive.