Multiselect Lookup Count

I have read several threads/forums on this but cannot figure out how to do what we need. We have an Zoho Creator application with a subform for Hotel Reservations for our clients. In the subform there is a Lookup multiselect from another database to list all employees available to be added to a reservation. I have tried various code and nothing is successful. We have a field named "Number" that we want to count the total number of employees selected from ProCon Employees multiselect lookup.