This video will show you how to use the Parallel sketch tool on the sketch toolbar in order to make two or more lines parallel.
First, select each line. Next, click on the Parallel tool on the sketch toolbar. The lines are made parallel to each other.
Constraints can be toggled on while you make selections. Toggle Parallel on, and each pair of entities you select are constrained to each other. Click Parallel again to toggle off, or select another tool to toggle off automatically.