Hello!
In orded to avoid further confusion I've decided to translate the parts concerning the weapons selector knob as well as some other things. The translation is as accurate and word for word as I can get.
"233. If the airplane is equipped only with guided missiles with infrared homing or with only R-3R missiles, then the order of their firing and the number of simultaneously fired missiles is selected through the weapon selector knob set in the proper position (positions 1, 2, 3 and 4 are meant for single launches, positions 1-2 and 3-4 for salvo in two launches, from their respective hardpoints.)
Attention. When setting the weapons selecotor knob in the setting 1 launch is executed in order 1, 2, 3 and 4. If setting the same switch in position 2, in order 2, 1, 3 and 4, in position 3 in order 3, 4, 1 and 2, and in position 4 in order 4, 1, 2 and 3.
(...)
237. If the airplane is loaded with infrared seeking missiles and R-3R, then their order of launching is determined through the postions of the "IR - NEUTRAL - SARH" switch (while launching infrared homing missiles it should be set to "IR", when launching R-3R missiles it should be set to "SARH"). If the switch is set to "IR", then after each push of the launch button the infrared missiles are the first to be launched, followed by R-3R missiles (in order 1, 2, 3 and 4). While set in "SARH", after each push of the launch button, the first to be launched are R-3R missiles, followed by the infrared ones (in order 3, 4, 1 and 2) if the weapon selector knob is set into position corresponding to single launches.
If the weapons selector knob is set to salvo fire, then the order of launch is determined by the setting of "IR - NEUTRAL - SARH" switch.
I've highlited the most interesting parts. It seems perfectly rational to have an automatic selection of the next pylon after firing one of the homing missiles. I can imagine that fiddling with a switch while in a hard fight with an enemy fighter could be very troublesome, so this would be a very needed feature in the real plane, and in DCS also!