Giving fleet subordinates custom default commands (e.g. creating trade fleets without mods)

Tired of having only defend, attack, intercept, and resupply as your only options for the default orders for fleet subordinates? Well do not worry, as custom default orders are actually not that difficult to assign.

First, assign the desired subordinates as you normally would to your desired fleet commander. Select the desired subordinates, then right click on the desired fleet commander and select "Defend commander” and choose the desired squadron position. Selecting defend, attack, or interception here does not matter, though I usually choose defend because if you forget to give the custom command, at least your trade vessel will not go on a suicide mission.

Next, take control of the fleet commander’s vessel. Now, you will be able to assign custom default orders to your subordinates! Simply select the subordinate vessel, go to the behaviors tab, and set their default order to whatever you want. If you want a trade fleet, set all subordinates to auto trade. If you want a taxi to dock at your capital ship, set your subordinate to dock and wait. I don't know if it was fixed, but the last time I tried a civilian fleet mod, it wouldn't let me give my fleets custom names. This vanilla way of creating trade fleets will however let you give your trade fleets custom names.

It's unfortunate such a great feature is so hidden, so hopefully this guide helped you learn something new!