The Variant 1 has a control lever on the left side of the pistol (right handed usage). This control lever, when flipped up as in the manner of a 1911 is a safety and allows C&L. When pressed to its lower stop, below the "off-safe" position, decocks the pistol.
Variant 2 is a duplicate of Variant 1 execpt with the control lever on the right side of the pistol (left hand usage).
Variant 9 has a control lever on the left side of the pistol (right handed usage). This control lever retains only the safety. Up to safe, down to fire, no decocking capability.
Variant 10 is a duplicate of Variant 9 execpt with the control leve on the right side of the pistol (left hand usage).
Most pistols for sale are Variants 1, and I would recommend you go to a shop and play with one, as it is easier to understand with the pistol in your hand.