Hello Tammy,
Classic Workflow can do simple parallel processing, but that's pretty much about it. There is a special "Group Start" and "Group End" Workflow Task, and everything between those marks is conducted "in parallel."
For your example:
10. This is my workflow task "1"! << It is executed by itself, first.
20 Group Start. << This starts only when 10 is complete.
30 My parallel task "2". << This can be done at any point.
40 My parallel task "3". << This can be done at any point.
50 Group End << Only completes when both 30 and 40 are done.
60 Another workflow task << Only when Group End is finished.
Thanks, Kyle_R.