I think it's like this:
30-29 Yrs. BSS - Orochimaru during his research discovers Madara is alive
30-29 Yrs. BSS - Orochimaru confronts Uchiha Madara and gets his ass handed to him. Uchiha Madara offers to spare Orochimaru's life if he works for him as a double agent, which he agrees to. Orochimaru's fascination with Sharingan Kekkai Genkai begins.
28 Yrs. BSS - Orochimaru starts to act differently threatening to kill the Ame orphans and joking about Nawaki's death, due to pressures of being a double agent corrupting him.
28-19 Yrs. BSS - Madara has Orochimaru join Anbu Root to gain Danzo's trust.
28 Yrs. BSS - Madara and Orochimaru give Nagato Rinnegan some how
22 Yrs. BSS - Madara/Orochimaru/Tobi manipulate Yahiko to start Akatsuki
19 Yrs. BSS - Madara has Orochimaru conspire with Danzo to in turn conspire with Hanzo to take down the Rain Trios organization, in-order to further Nagato's growth
19-14 Yrs. BSS - Orochimaru offers Danzo a deal where if he overlooks his experiments he'll give him the product of his research.
17 Yrs BSS - Kakashi Gaiden happens. Madara discovers the dying Obito in the rock avalanche and uses Zetsu goop to save his life
16-13 Yrs BSS - Madara corrupts Obito, culminating in the death of Rin, turning him into Tobi
14 Yrs. BSS - Kushina becomes pregnant and Madara has Orochimaru set up a meeting between him and Danzo.
13 Yrs. BSS - Madara tells Danzo if he can distract the Uchiha clan and tell him the night Kushina is going to give birth that, together they can wipe out the Uchiha Clan, which will allow Danzo get his hands on their eyes and enough power to become Hokage.
13 Yrs. BSS - Orochimaru under some emotional duress from knowing about the events he's about to allow to occur becomes sloppy and Hiruzen discovers his experiments forcing him to flee the village
12 Yrs. BSS - Danzo has Shisui use Kotoamatsukami on Fugeko to call a meeting. Naruto is born. Madara sends his apprentice Tobi to extract the nine tails. Minato and Kushina die resulting in Kurama being sealed into Naruto.
12 Yrs. BSS - Hiruzen suspects there is a traitor in the village, so he tightens security in the village and around Naruto preventing Madara from making a play for Kurama. Villagers begin to suspect the Uchiha clan of foul play due to their failure to show up that night.
11 -8 Yrs. BSS - Madara approaches Danzo again and asks for his cooperation in taking over hidden mist to create a new organization to surpass Anbu Root, which will help them achieve their end goals.
7 Yrs. BSS - Danzo has Shisui travel to root and use Kotoamatsukami to control the Mizukage to obey Madara.
7-6 Yrs. BSS - Akatsuki officially becomes the crime syndicate it is today through using the resources of the hidden mist village. Tensions continue to rise in the leaf with people blaming the Uchiha clan for Kurama's attack.
6 Yrs. BSS - Madara and Danzo decide the time is ripe for the Uchiha clan to be wiped out, Danzo offers the mission to Shisui, but Shisui due to everything he had seen pieces together that Madara and Danzo have been plotting all along to cause the destruction of the clan and rejects the mission leaving Anbu root.
6-5 Yrs. BSS - Madara and Danzo set their sights on Itachi to carry out the mission. Shisui feeling remorse and wishing to stop Madara travels to mist and tells AO someone is controlling the Mizukage. AO confirms this with Byakugan and Hidden Mist is liberated resulting in the death of Yagura and Sanbi going wild. Shisui alerts Fugeko that Danzo is aiming to destroy the clan, which cause the Uchiha to start planning their rebellion.
5 Yrs. BSS - Shisui confronts Danzo trying to stop him, but Shisui is defeated and loses his eye and arm to Danzo. Shisui on the verge of death confesses everything to his best friend Uchiha Itachi giving him his other Sharingan eye.
5 Yrs. BSS - Danzo will only agree to make the final move to destroy the clan if he sees some result from Orochimaru's experiments, so Madara makes a deal with Orochimaru that he'll give him Itachi's body if he implants Hashirama's DNA into Danzo. Orochimaru agrees to this.
5 Yrs BSS - Danzo uses the suspicion of the village against the Uchiha to turn the Elders against them. Hiruzen tries reason but fails. Danzo tells Itachi the only way to save the village and his brother is to massacre the clan.
4 Yrs BSS - Itachi seeks out Madara and Madara agrees to help him massacre the clan
4 Yrs BSS - Itach and Madara massacre the clan. Madara out of his lust for revenge does this personally rather than sending Tobi. Madara collects most of the Sharingan betraying Danzo who he promised the Sharingan to and never has Orochimaru complete the integration of Danzo's DNA.
3-4 Yrs BSS - Orochimaru goes to claim Itachi's body from Madara, but Madara betrays Orochimaru alerting Itachi to Orochimaru's intentions and gives Itachi a great deal of intel on Orochimaru's abilities ensuring his victory. Itachi defeats Orochimaru. Orochimaru betrayed and unable to beat Itachi leaves Akatsuki
3-4 Yrs BSS - Orochimaru realizes that Madara will die shortly from the strain he put on his body during the massacre
3-1 Yrs BSS - Madara dies, leaving his apprentice Tobi in charge with the order to use Gedou Rinnei Tensei to revive when the tailed beasts are captured.