It depends on how much visibility you need/want. For example here is an approach that is probably not used very often but is simple and easy to update. This example shows 4 steps to produce a single drone with the time span needed to produce a quantity of 20 drones for each step. Since steps are consecutive, each step's predecessor is expressed as a percentage delay from the start of the previous step. In this example, step 1 is complete for the first drone (1/20 = 5%).
If you need finer detail on the plan, this simplistic approach could be parsed into groups of 20 or 50 (i.e. 10 groups of 20 each or 4 groups of 50 each) by replicating the above. However, if you need full detail for each drone, then the best approach is to replicate the process for a single drone for the full quantity which would be a copy/paste.
There may be other ways to approach it, it all depends on what kind of process visibility you need.
John
