Learn the basics
Here's a handout that introduces the basic vocabulary and ideas of argument visualization. For interested readers, the hints page, adapted from feedback I wrote for Princeton students, goes into more detail. I hope to soon add some videos that will introduce argument visualization to beginners in the context of interesting philosophical arguments. You can join the PhilosophyMapped mailing list to find out about when I post new resources.
Practice with multi-choice-guided mapping problems
For extra practice with the basics of argument mapping, you may wish to attempt some of the exercises embedded below.
Begin by selecting an argument from the list. They are ordered by difficulty from Level 1 - 4, with 1 being the easiest. Begin by copying the text of the argument into a MindMup file and mapping the argument for yourself using the conventions explained above. Once you're satisfied with your map, go back to the multiple-choice exercise and work through the questions, using them to check your work. Once you have finished the questions in a particular exercise, the suggested solution will be fully revealed.
When your own map disagrees with the solution, make sure you understand where you went wrong: These exercises are only beneficial when you reflect on the feedback.