Supreme Leader Snoke is the secondary antagonist in the Star Wars sequel trilogy, first appearing as a major antagonist of Star Wars Episode VII: The Force Awakens, and he returns in it's sequel Star Wars Episode VII: The Last Jedi as the main antagonist.
Speaking about BB8
He at first appears calling Kylo Ren and General Armitage Hux and talks with them about the rise of newborn Jedi. Hux introduces his weapon to Snoke, telling him it can destroy the Resistance and their supporters which are The Republic. Snoke agrees, and tells him to oversee preparations. Hux leaves the room, and Kylo Ren stays inside. Snoke then tells Kylo Ren about the awakening, and informs Kylo Ren that the droid The First Order is after, is located inside The Millennium Falcon, owned by his father, Han Solo. When Kylo Ren said it means nothing to him, Snoke tried to convince Ren that even he hasn't faced such a test.
Later, when Kylo Ren takes Rey as his hostage, and fails to read her mind with the force, Snoke calls Kylo Ren again and asks him angrily if the girl really resisted him. Kylo Ren tried to protect her by claiming that he is stronger. However, Hux enters the room and interferes, stating that because of him, the map had most likely been returned to The Resistance. Hux and Snoke agreed on destroying The Resistance. As Hux exited the room, Snoke ordered Ren to bring Rey to him.
The destruction of The Starkiller Base
Hux prepared for retreat and told Snoke about his failure. Snoke was fed up, and he told Hux to leave the base at once with Kylo Ren, and come to him
Betrayed by Kylo Ren
After Hux looses another battle against The Resistance, Snoke gets upset, and uses his hologram to call Hux into the throne room. Hux manipulates Snoke into agreeing to another scheme against The Resistance. After that, Snoke calls Kylo Ren "a child in a mask", as he begins to doubt in Ren's capability. Hux uses a new tracking device to locate The Resistance's starships, and plots to destroy The Resistance by surrounding The Rebel ships and attacking them as they struggle their way to a mineral planet. Kylo Ren brings Rey to Snoke, as he was secretly helping her against him. Snoke uses the force to take Luke's lightsaber from Rey. Snoke revealed that he has manipulated both Kylo Ren and Rey to get to Luke Skywalker, and after he tortured Rey, he ordered Kylo Ren to kill her. Kylo Ren however killed Snoke instead, and therefore, both Hux and Ren take his place as Supreme Leaders.