Short answers, pulled from the story.
The Russian Ground Forces were officially established on the 7th of May 1992 when President Boris Yeltsin signed a decree creating a new military structure following the dissolution of the Soviet Union.
Crime rates within the Russian military soared during the chaotic transition period with a reported 40-percent increase in crimes over six months ending September 1990 including a 41-percent rise in serious bodily injuries and rampant disappearances of weapons.
The First Checen War began on the 11th of December 1994 when Russian forces entered Grozny the capital of Chechnya and ordered the 131st Motor Rifle Brigade to push toward the city center where it was virtually destroyed in ambushes.
A major reorganization began in 2007 under Minister for Defence Anatoliy Serdyukov aiming to convert all divisions into brigades and cut surplus officers which resulted in 85 brigades of constant combat preparedness by the 1st of June 2009.
As of the 6th of May at least 12 generals have been killed in Ukraine according to the Ukrainian Ministry of Defence suggesting that commanders need to be at front lines to ensure battle plans are conducted correctly.
By 2025 the International Institute for Strategic Studies estimates the Russian Ground Forces will include 550,000 soldiers comprising about 100,000 conscripts with recruitment efforts reportedly between 400,000 and 500,000 contract soldiers each year since the invasion started.