Short answers, pulled from the story.
Impeachment in Russia is a constitutional process under Article 93 that lets the State Duma indict a sitting president, with the Supreme Court and Constitutional Court reviewing whether the correct procedure was followed. The Federation Council then holds the final vote to remove the president from office, and both stages require a two-thirds majority.
Impeachment in Russia has been attempted three times, and every attempt targeted President Boris Yeltsin. All three attempts failed to remove him from office.
The first impeachment in Russia against Boris Yeltsin took place on the 28th of March 1993, over an accusation that he had violated the Constitution. The vote reached 617 votes, short of the 689 majority required, so it failed.
During the September 1993 impeachment in Russia, parliament declared Boris Yeltsin dismissed de jure on the 22nd of September 1993 and handed his duties to Vice President Alexander Rutskoy. Yeltsin remained in office de facto, declared the dissolution of the Supreme Soviet, and the standoff escalated into the armed 1993 Russian constitutional crisis, which he survived in power.
The 1999 impeachment in Russia, held between the 11th and the 15th of May, brought five charges against Boris Yeltsin, and none reached the 300 votes needed. The closest was the charge over the war in Chechnya, which drew 283 votes, seventeen short of the threshold.
Impeachment in Russia requires the State Duma to vote for indictment with 300 votes, two thirds of the chamber. The Federation Council must then vote to remove the president with 114 votes, also two thirds, within three months of the Duma bringing charges.