First, review past tense verbs with them. I added a lot of too-complicated stuff about irregular vs. irregular verbs so feel free to delete that. Then we review the vocabulary. Next is the Pikachu story time! Students choose between present and past tense for the story. I usually conduct this as a full class. I have students repeat all the sentences, both tenses, and sometimes I'll ask a student to translate if I don't think everyone understands, and then ask one student to call out the answer. Pretty simple activity!
https://docs.google.com/presentation/d/1qpMXAopXOtOEEpeznMFzi9wFwAKQyML-MpSBv_5ixEM/edit?usp=sharing