Need help choosing a sump system

[Spicoli]

So I am a new member on this amazing site and with this hobby. I have purchased a used 90gallon reef ready tank with stand and now I'm beginning my research in choosing what I should use for a sump filtration system. What i was leading towards was the basic tank with overflow and a skimmer and internal pump but now I'm reading up on the Eco system, which leaves me confused. Can anyone share some ideas or what they found best?

Thanks,

Spicoli