You can help them to understand past and future tenses by practising talking ... you could prompt them for more detail. So for example, if they say 'we built a sandcastle', you could ask 'what ...

writers usually use the past tense close past tenseA verb tense ... Writers don’t generally use the future tense close future tenseA verb tense expressing an action that has not yet happened ...

One would use past tense to summarize one’s results Example: “In the future to further this experiment, we would expand this project and expand our sample size in order to have a more solid base for ...