1989 - Milosevic becomes president of Serbia
1991 - Civil war begins in the Balkans
3 March 1992 - Bosnia and Herzegovina declare independance
April 1992-1995 - Muslims and Croats are killed in ethnic cleansing (Bosnian Genocide)
I am not so sure what you mean by "what kinds of unions were formed", but if you're talking about the Civil War then I think the unions were Confederate and Union. The Confederates wanted to run the country with slavery while the Union fought against slavery. Do not quote me on that though.
The answer would be summer because it gets really hot during that time
