can someone explain how the whole tribute thing works, i'm not 100% sure on it.

"Tribute" in Mafia has several dimensions. But, basically, think of Mafia life as a kind of franchise pyramid scheme. If you're an associate or a simple "soldier," you have to kick back part of your earnings (sometimes more than half) to your capo or crew chief, who keeps some and passes the rest on upstairs until the remainder reaches the Don. That's a "tribute" but I'd call it a franchise fee--the soldier's right to operate a racket under the auspices of the Don's family. In other cases, a "tribute" can be a special levy that the Don imposes on other Mafiosi as a power play--simply because he can. Joe (the Boss) Masseria precipitated the famous Castellemmarese War of 1930-31 by declaring himself capo di tutti capi and demanded tributes from Castellemmarese family bosses around the country. Salvatore Maranzano, the victor in the war, declared himself boss of bosses andimposed such a tribute on all of the 600-odd NYC Mafiosi who survived the war. That led to his demise.

Okay but, lets say Al Neri pays tribute to his superior, the caporegime Pete Clemenza. Does Pete Clemenza have to pay Al Neri for working for him?

No. If the Corleones were following the typical Mafia operating system, Neri would kick back part of his earnings to Clemenza, and Clemenza would simply regard that as his due for having brought Neri into the family and sponsored him. In the novel, Neri kills Moe Green and is rewarded by being given a "particularly rich East Side book" to operate. Presumably, part of his earnings would be kicked back to Clemenza, who would also send part to Michael.

Speaking of tributes. Joe Fishetti, a cousin of "Scarface" Al Capone invited Frank Sinatra to stay with him in Miami for a few days then fly to Havana to meet Lucky Luciano. when they arrived in Havana, Fishetti together with his brother and Frank carries "Two" attache cases which the investigators suspected has two million in it as a tribute to Lucky Luciano(reminds us of Fredo when he brought the money in Havana).
Frank Sinatra gave Luciano a solid gold cigarrete case inscribed "To my pal Charlie, from his friend Frank Sinatra."

GoodFella

what about family tribute, would Sonny have to pay tribute to his dad, Vito Corleone?

Good question, Johnny. I'm guessing that Sonny would have to kick part of his earnings into a "family pot" (my phrase, not Puzo's) that would pay "administrative expenses," such as for the upkeep of the Mall (where Sonny and his family lived), as well as for Hagen's salary and family expenses (Hagen, as consigliere, was a Corleone Family resource and didn't bring money in directly since he didn't have a regime.) Fredo probably had some action of his own, and had the same arrangement. The "family pot" no doubt also paid for Michael's college tuition before he took his irrevocable step into the business.