Purpose: This tutorial is an introduction to first phase syntax (FPS; Ramchand, 2008). FPS provides a new, cross-linguistically motivated perspective on clause internal structure. A new sequence of syntactic development is proposed based on FPS with 4 levels of complexity: (0) verb particles and adjectives in the 1-word stage, (1) semantic relations of entity + location/attribution, (2) intransitive structures encoding change of location/state, and (3) transitive sentences with an internal argument that changes state/location and an external, causer argument. A novel prediction of this framework is that a Level 2 structure emerges earlier than a Level 3 structure. Method: Archival longitudinal data of 15 children (8 boys) were selected to test the proposed developmental sequence. The 15 children's data were drawn from the DeKalb corpora (Rispoli, Hadley, & Holt, 2008, 2009) and Champaign corpora (Hadley, Rispoli, Holt, Fitzgerald, & Bahnsen, 2014), selected because their mean lengths of utterance did not exceed 2.54 at age 2;6 (years;months). One-hour language samples taken every 3 months from 1;9 to 2;6 were searched for Level 1-3 structures. The diversity of the internal argument was tracked across levels. Results: Average argument diversity shifted across levels over the period of 1;9-2;6. At 2;0, argument diversity was highest for Level 1; at 2;3, diversity was highest for Level 2; and at 2;6, it was highest for Level 3. Paired-samples "t" test revealed that, at 2;3, argument diversity in Level 2 was significantly higher than that in Level 3. Conclusion: This developmental application of FPS provides a theoretical framework for a developmentally ordered sequence of syntactic goals and treatment targets for children struggling with the acquisition of syntax.