Throughout the school year, we use a variety of tenses so that students have a natural feel for using them. Generally, a textbook curriculum might only allow for students to focus on one tense. The results of doing that have shown that students take a bit longer to figure out for example, using preterit and imperfect tenses together.
Here, students start hearing past tenses in the second week of the school year. In this clip of a Spanish 1 class, I am narrating in the past while speaking with students in the present tense. The the most natural way for me to do this is to retell stories or parts of a story in the past. Because student already comprehend the story it is an easy way to build on prior knowledge.
At this level, subsequent formative assessments might include; students translating a different story in the past, writing story retells using the past tenses, and lastly, (when ready) retelling stories or new topics using the past tenses.