What type of text provides guidance, direction, or instructions on how to do something?

The sentence 'Sit up straight in your chair.' is a type of what kind of sentence?

Which of the following is NOT an example of a command sentence?

In which sentence is the prohibition found in the following procedure: (1) Heat wax in a pan with low heat until it melts. (2) Do not use high heat to maintain the stability of the stove temperature. (3) Take wax using a canting. (4) Paint the white cloth with the canting according to the pattern on the cloth.