I've found that commanding your allies is pretty basic but there are some useful tricks to it. You can get them to follow you around by cycling through commands, and if youre lucky they'll actually listen. The bodyguard system is probably the most reliable part, where you can at least tell your personal squad to be aggressive or hang back and defend.

Something that took me a while to figure out is that you can actually place markers on the map to guide your troops, though honestly they don't always follow directions super well. I've noticed they tend to get confused especially when fighting officers, and sometimes they'll just stand there after finishing whatever they were doing.

The best approach i've found is to just lead the charge yourself and let your allies follow your example. They usually respond better when youre actually in the thick of it with them, and even though you cant give super detailed orders, they'll generally try to help out when youre nearby. Its not perfect but it gets the job done if you work with what youve got.

Oh and interesting tip - in some of the newer versions you can actually get allies to target specific officers, but don't count on them to finish the job since they cant land the final blow on commanders anyway.