Complex sentence: At the conference, Stojanović installed Milorad Mijatovića Partisan from Kozaraas the new commander of the 1st Krajina and Petar Vojnović as deputy commander, while Velimir Stojnić and Salamon "Moni" Levi remained as commissar and deputy commissar, respectively.
Split into simpler sentences: At the conference, Stojanović installed Milorad Mijatović, a Partisan from Kozara, as the new commander of the 1st Krajina. He also installed Petar Vojnović as deputy commander, while Velimir Stojnić and Salamon "Moni" Levi remained in their capacities as commissar and deputy commissar, respectively.