The article presents a methodical method of determining the influence lines in statically determinate bar structures (beams, frames), and the method of drawing up the envelope for moving loads. The lines of influence for simple systems are presented, which makes it possible to draw up L for complex systems. The construction of drawing up such lines of influence is outlined in detail. The method of the kinematic method of preparing lions is given. Additionally, indirectly loaded systems are considered for which lw must be prepared in two stages, as demonstrated by examples. It is given how lw can be used to determine extreme static quantities, and an example of determining the envelope of moving loads is given. The article is a help for students of the Faculty. Civil engineering, engineering studies.