To place a linear form parallel to another linear form

Select the Place Form Parallel tool.
From the Method option menu select Form.
From the Top option menu, specify one of the following options and perform the subsequent steps:

Choose Fixed Height and continue with the next step.

or
Choose Connect Shapes. To set the form's height to that of existing shapes or forms to connect to, select those shape(s) and/or form(s). Confirm the selection with a data point. Reset to continue.

or
Choose Connect 3pts and then place three data points to define the plane in which the top face of the form is located.

or
Choose Connect 2pts/View and then place two data points to define an imaginary line. Enter a data point in the view that the top face's plane is perpendicular to.
Identify a linear form the new form will be placed parallel to, and accept with a data point.
Enter a data point to define the start point of the parallel linear form.
A line starting from this point and parallel to the selected form displays dynamically.
Enter a data point to define the end point of the parallel linear form.
This point is projected on the parallel line. The projected point is the end point of the new linear form.
(Optional) Go back to step 4 to place another parallel linear form.

Placing a larger linear form parallel to a smaller linear form