from few other samples I could find, these really are "instructions" i.e. are far more detailed and obligatory than just "guidelines"
http://www.mpn.gov.rs/wp-content/uploads/2017/05/стручно-упу...sounds more like "instructions given by the Ministry's experts" rather than "instructions to experts", although it could also be "струка" as in "type of activity" "instructions for those doing this type of activity"
You do get a type of document issued by a Ministry called "instructions", but to be really sure you would need to compare in Serbian few documents called "смернице" and few "стручно упутство" to establish what's the difference and then few "guidelines" and "instructions" by a ministry to see which one would fit. I have no time for that.