Go to 'Settings -> Integrations'. Select 24SevenOffice from the list of integrations.
Click the "Connect to service' button. This will open 24SevenOffice. Enter your credentials to login to 24SevenOffice.
You will then return to MakePlans to select which MakePlans account to connect to. Select your account.
The next step is to define the payment terms for the order generated from MakePlans.
And finally you have to link a service in MakePlans to a product in 24SevenOffice.
That's it. MakePlans will now automatically add a new customer in 24SevenOffice when a new customer is created in MakePlans. You can also manually generate an order in 24SevenOffice from a booking in MakePlans.