Been over 20 years since I did any S5 so the memory has degraded a bit but here goes:
UN = Bitwise AND NOT
SPB = Jump conditional to the label (JC in English) JU is jump unconditional JNC is jump if not (sorry cannot remember German unconditional jump)
*** = Segment end (end of ladder instruction)
L = load value into accumulator 1 (note L KF+1 L KF +10 first moves 1 into accumulator 1 then the 1 into accumulator 2 and 10 into accumulator 1).
T = transfer to a memory
MB = Marker byte (memory byte)
MW = Marker Word (memory word)
C DBxx is call of a data block i.e. Call Data block 10 (data blocks are areas of retentive memory in blocks of 255 words (on larger PLC's can be used as larger blocks with special addressing).
DW is a Data word of the called block
UW = AND word
ON = OR NOT bit
O = OR Bit
U( AND Function
) end of AND function (Note can be OR O( or AND U(
S = Bit Set
R = Bit Reset
= is Equals i.e. an output instruction (true or false)depending on the preceding logic
><F = Not equal
!=F = equal
>F = Less than
<F Greater than
Note: KF is fixed point (integer), KG = Float KH = Hex
TAK means swap accumulators (often used after a math function to put the first value back into Accumulator 1).
There are many instructions so as said before you really need the S5 manual for STL. in S5 Function blocks cannot be displayed in ladder only program blocks so in reality the *** segment end are not strictly required also jumps cannot be done in program blocks. I believe that Ladder in function blocks only appeared in S7.
OB = organisation block, OB1 is the main cyclic block used to call the other blocks but other blocks can be called within blocks.
There are other OB's for interrupt, time, start up etc.
Hope this may help....
Just found this probably would have saved me having to rack my brain but the instructions are in English i.e. A instead of U etc.
https://cache.industry.siemens.com/dl/files/150/1086150/att_1992/v1/948then.pdf