Short answers, pulled from the story.
The Battle of Molodi was fought in July and August 1572, near the village of Molodi approximately 50 kilometers south of Moscow. The armies first clashed near the Lopasnya River on the 30th of July, with fighting reaching its peak on the 8th of August.
Prince Mikhail Vorotynsky held supreme command of the Russian forces at Molodi. The flanks were led by Prince Repnin on the left and Prince Odoevsky on the right. Prince Dmitry Ivanovich Khvorostinin played a decisive role by maneuvering mobile fortifications around the Crimean rear.
Devlet I Giray, the Crimean khan, led the attacking force at Molodi. His army included Nogai and Circassian troops as well as janissaries sent by the Ottoman Sultan, and was equipped with cannons.
Gulyay-gorod were mobile fortifications used by Russian forces at Molodi. They could be moved across terrain and served as platforms for artillery and arquebuses. Prince Khvorostinin used the gulyay-gorod to bypass the Crimean horde and attack its rear, which proved decisive.
Only 20,000 Tatar horsemen returned to the Crimea after the Battle of Molodi. Devlet I Giray fled the field, leaving behind his tent and banner. The battle also killed two of his sons and a grandson.
Devlet I Giray attacked Russia a second time because the Tsardom was engaged in the Livonian War, leaving its southern borders exposed. His 1571 raid had successfully burned Moscow, giving him reason to expect a similar result. Contemporary sources indicate he crossed the Oka River near Serpukhov on the 26th of July 1572 with the intention of pillaging Moscow once more.