In 19 BBY Chancellor palpatine declared the republic an Empire with himself as emperor. For 19 years he ruled almost all of the galaxy relatively unnoposed until the first Death Star was destroyed by a team of rebels led by Luke Skywalker. After this attack the Rebel Alliance was seen as a serious threat and 4 years later they destroyed the second death star killing Darth vader and the emperor in the process and restoring peace to the Galaxy
The most common soldier of the empire was the regular Imperial stormtrooper they were usually equiped with an E-11 blaster a thermal detonator and the iconic white armour with a skull shaped helmet. Their armour provided limited protection from blaster bolts and small explosions. Their helmet could provide them with oxegeon and filter out smoke, their armour also allowed them to survive in space for a short period of time.
The cold assault troopers also known as snowtroopers specialised in battles in extremely cold enviroments. They were deployed on worlds such as Hoth. Their armour kept the trooper warm while also protecting them. Their helmet allowed them to breath easier in these enviroments. The trooper was equipped with terrain-grip boots, a standard utility belt containing high-tension wire, grappling hooks, ion flares, additional blaster ammunition, a survival kit, and ration packs.