how do you tell a captive what do do
Unemployed captives take jobs wherever there are vacancies. The only way of moving them is by firing them then others take the job (unless you close it off), or press-ganging (converting into a pirate).
kill a disgruntled pirate
There is an edict to assissinate any character. Problem with this is costs $100 and takes time, and sometimes the target kills the assassin. Easier to give the $100 to the pirate (edict: donate money to pirate, there is a shortcut button top right in the window when the pirate is selected); they will spend most of it quickly.
You could issue the edict betray all pirates of the same nation as the disgruntled pirates. OK if there are few pirates of that nation; you also get improved diplomatic relations with that nation. Beware, captains of that nation are killed too if they are not at sea.
Is there a page i could look up stuff like this
I got a small manual booklet with my Tropico2, and played the campaign.