How did Ukraine join Russia?

The annexation of Ukraine to Russia dates back to 1654, it went down in history as the Pereyaslavskaya Rada, a monument to this event stands in the city of Pereslavl-Khmelnitsky in Ukraine, not far from Kiev.

The background is as follows: Since 1648, there have been three wars of the Cossacks under the leadership of Bohdan Khmelnitsky. The first was successful and ended in 1649 with the Zboriv Treaty, in 1651 a new war ended with the less successful Belotserkovsky, and in 1653 the more successful Zhvanetsky. Bohdan Khmelnitsky was betrayed by the Crimean Khan three times, so he decided to turn to Tsar Alexei for support.