To synchronize at any time, run the Synchronize with TheBrain Cloud Services command on the File menu if you are on version 7, or the Online menu if you are on version 8, or you can also click the double arrow in the top toolbar, below the menu options.
You can keep working while the synchronization process is continuing in the background. If there is an interruption during an initial upload of your Brain, TheBrain will offer to resume from where it was stopped the next time you synchronize.
If you make changes on either computer, you will need to remember to synchronize, or you can set your sync to "Sync this Brain automatically", and it will sync approx. every 10 minutes.