To Create a Chained Linear Dimension from an Origin

Select the Linear Dimensioning tool.
Set the mode to Linear Single.
Enter a data point to define the dimension origin.
Enter a second data point to define the length of the extension line (the offset distance from the origin to the dimension line).
If Alignment is set to Drawing or View, this data point also defines the dimension axis.
Enter a data point to define the endpoint of the dimension.
If Location is set to Manual, enter a data point to position the dimension text.
Do one of the following:

Go back to step 5 to dimension another location from the same origin.

or
Reset to place the dimension in the design.
(Optional) Do one of the following:

Go back to step 4 to dimension locations in a different direction (turn the corner), using the previous data point as the origin.

or
Reset and go back to step 3 to start a new location dimension from a different origin.

Creating a Chained Linear Dimension from Origin (Location set to Automatic)

Creating a Chained Linear Dimension from Origin (Location set to Manual)