This paper intends to offer a practical case of application of Systemic Functional Linguistics (SFL) to Foreign Language Teaching (FLT). While there is research offering very interesting insights for the application of SFL to Foreign and Second Language teaching contexts, none of it provides a straightforward application of SFL to the actual design of lessons. The proposal first focuses on how to create a text that contains the lexicogrammar object of study of the lesson. After this, and using the VLE (Virtual Learning Environment) Moodle, a series of activities are proposed, moving from more guided to more open-ended, all of them driven by the didactic exploitation of the lexicogrammar of mental processes. The proposal integrates SFL theory into the explanation of the lesson’s (lexico)grammatical goals. As part of this, the convenience of using system networks in FLT, e.g. the system network of mental clauses, is discussed.