What I try to do with them to help crystallize their understanding of how Spanish verbs differ from tense to tense is have them co-construct a verb chart based on meaning first and then we make sure the forms are in the right spot. BUT, BUT, BUT I do not suggest doing this until after they have been working with the tenses for a while. This is NOT something to do with them to front load grammar. This is a review activity to give organization to what they have learned. If you do it the other way, you will be disappointed with what effect it has on their communication. The goal is to take what they know and organize it in hopes of strengthening the link between form and meaning and improve their accuracy in choosing which tense they use to communicate with.
Also know, this is really not about conjugation at all. It's more to do with communicating time frame.
When you do this with your students don't just hand out the completed form. I suggest going to your board and working this out with them by asking them questions. Have THEM tell you want to put where. Then, when the work is done and matches what you intended the chart to look like in the first place, hand them this handout or have them design their own!
Link to Word Document
Link to PDF Version