One thing I see frequently as a college professor is students who switch tenses. One moment, they are talking about something that has already happened and the next minute they are in the present and sometimes even go into the future. In the same sentence. Whoops!
Here’s the key: If you are reporting on something that has already happened, put it in the past tense. For example, let’s say that you are writing an essay about how your group did on a group project for the class. It has already happened, so it is in the past. Perhaps you might report “our team worked together quite well.” You would not say “our group is working together quite well” because it already happened. The first example says that you already did your group project, while the second sentence suggests that you are still working on the project.
If you will continue to work with the team but you have already done one project, you might write something such as “our team worked very well together on our first assignment. We will continue to collaborate in the second assignment.” This indicates past and future tenses, since you already did something and you will do something else in the future.
To say that you did something and you are doing something now, you might write “our team worked together very well on the first project and we are already collaborating on the second project.” This is past and present tense, since you did something and you are still doing it.
The person in this picture is walking from the past, is in the present, and is walking towards the future.
I hope this helps!