Getting into HoI4 for the first time and have some questions

[CraniumMuppet]

Thanks for this, kind of bugs me that the symbol changes but the name doesn't

So what's the difference between a navy and a task force and why do I have crossover?

1 fleet= 1 or more taskforces
1 taskforce = 1 or more ships
Navy usually refers to all fleets that you have

 

[CraniumMuppet]

Another question, how do I increase the amount of guns used in a coup? When I look at the option to start one, it usually says something like "will use 1200 infantry equipment". Seems a bit small for overthrowing an entire government when a single division can use that many men

The strength of the coup depends on the party popularity. So if you are fascist the strength of the civil war will be the targeted countrys fascism support.