The software is pretty self explanatory. Just play around and you will get a hint of it. Couple of useful tips:
- Open a Checkmark To Do List Manager database file. (If you are using Dropbox Sync, the file named Checkmark should be in the Dropbox home directory under Apps/Checkmark To Do List Manager/.
- After done editing the file, save it and it will sync to Dropbox.
- Use Dropbox sync feature from your phone to sync Checkmark database to/from Dropbox folder.