Assalam-o-alaikum!
Ok. Your structural engineering and field work should be as per the books and design codes you have been following during your engineering education.
In the structural engineering field, you would generally be required to understand and apply analysis and design concepts and procedures taught in various structural subjects, during your engineering education. Here, you will be involved in structural design of a variety of civil engineering structures, and in doing so will refer to various design codes.
Following thread will give you an idea about the design codes, generally being followed and referred for practical designing of civil works in Pakistan:
http://www.sepakistan.com/topic/1329-sefp-consistent-design/
For the structural design of various structural element (e.g., RC slabs, beams, columns, etc.), you would be following the design procedures given in your relevant (RC) design textbook, and the design code (e.g., ACI 318)
In the construction field, you would either be supervising construction work based on structural drawing prepared by some other structural engineer (as per above referred design codes), or prepare cost estimates for the same based on applicable schedule of prices. The basic field procedures used in the field work, are essentially similar to those taught in engineering universities in various construction related civil engineering subjects.
Regards.