It can be divided into different phases, but suffice to say...
In the early going, the main Qing military was the 8 banner system, which seperate different Manchu and Mongolian Tribes into banners. It was sort of a military caste like system where the Bannermen are given fiefs and they must produce men to fight in times of war.
Their main strength was horse archery, though they could really be anything from heavy infantry to light infantry or gunmens etc... their primary armour was a heavy brigadine style armour like this.
The Qing also absorbed the Ming military into the "Green Camp" which was more predominantly infantry / gunpowder units.
But as time went on the 8 banner system began to fall apart as many Manchus were now living a confortable life in China instead of the harsh tribal existance in Manchuria, the Mongolian 8 banner remained relatively more effective until the mid 19th century when they were destroyed in the Opium war and later on the many internal rebellions.
The Green Banner lasted a bit better than the Manchurian 8 banner but also failed badly by the 19th century.
In the Taiping Rebellion phase, the Qing began to raise milita army by certain officials from their homeland (called the Xian Army and Huai Army). these militas succeded in defeating the rebels and became the bases of the New Army. which was suppose to mimick western style military of the era.
Unfortunately poor political commitment and the lack of a real industrial base to support such armies made it a failure, the Qing lost many state of the art ships in the Sino-Japanese war of 1895. and after that they were basically restricted to only an army.
Despite their defeat, the new army (called the BeiYang) began to gain ever more political clout and in the end they played a big part in overthrowing the Qing, and the resulting situation in China until the Communist victory in 1949.