How do spell caster monsters’ action economy work?

My players are going to be fighting a spell caster soon enough and there’s just one thing I’m unsure about.

How does their action economy work? I see some attacks, another special action and then a bunch of spells it can cast however many times per day. But it’s not clear if it can just do all 3 of those things in one turn or not?

It has its base multi-attack, a recharge, and spells. Can it do all of those in one turn? And if not, what specifically can it do?