Short answers, pulled from the story.
The dispute escalated when Soviet Premier Nikita Khrushchev refused to approve a preliminary agreement on the eastern section of the border after Mao Zedong publicly stated that Russia had unilaterally incorporated Siberian territories as far as Kamchatka. This leak outraged Moscow and halted negotiations, setting the stage for escalating tensions throughout the late 1960s.
A group of People's Liberation Army troops ambushed Soviet border guards on Zhenbao Island on the 2nd of March 1969. The battle lasted about two hours starting around 11:00 when Chinese forces attacked an unsuspecting Soviet patrol.
Soviet sources claimed at least 32 Soviet border guards died with 14 wounded during the fighting. Five Soviet soldiers received the top honor of Hero of the Soviet Union for bravery during the conflict including Colonel Demokrat Leonov who was killed by a Chinese sniper while leaving a destroyed vehicle.
The decisive event stopping escalation into all-out war was Ho Chi Minh's death on the 2nd of September 1969. His funeral allowed messages to be exchanged between Soviets and Chinese via North Vietnam leading to peace talks.
Russia and China signed a border agreement resolving final disputes on the 14th of October 2003. China gained control over Tarabarov Island, Zhenbao Island, and around 50% of Bolshoy Ussuriysky Island near Khabarovsk following this agreement.