I have a question on setting up a problem to find the reactions and forces in members of trusses. So initially I find the reactions at the pins using a free body diagram, I get that. However, when I need to find the forces of the particular members am I supposed to take an initial guess as to whether or not the forces are compressive or tensile and then based on whether or not I get a negative for my result proves the accuracy of initial assumption? Or do I analyze the loads being placed on the structure and should it tell me from observation what direction the forces are going? Any help is greatly appreciated.