Once a stub program has been created, we can proceed to replace stubs with working code.
Implementing program logic
Filling in the blanks
Now that we have code stubs and a map of each feature that needs to be implemented, we can begin writing the code logic. At this point, if you are working on a team, then this would be a good time to divide the work. The architecture phase may be done by one person, or as a team, but it can't be done in parallel. In contrast, the implementation phase can be broken into parts to work on separately.