Filemaker global database fields are unique to each user and that can be a problem if you want to share your Filemaker Pro database with Filemaker Go clients via your network. Basically, if I update a global field on my MacBook via Filemaker Pro, those updates are not reflected in when I then access that database via Filemaker Go.
Step 1 - Setup Table
The way around that — or at least one way around that — is not to use global database fields at all. What you can do instead is to set up a table with one record in it and use the fields in that table as pseudo-globals. It's probably easiest to use a serial number for the ID record rather than a GUID in this instance, so the one and only record in this table with have the serial number 1.
Step 2 - Configure Access
Then in any table that needs to reference the globals table, you just set up a number field that always contains 1.
Step 3 - Setup Relationship
Then you join those two tables and access your pseudo-globals via that relationship.
Filemaker uses the term global in a strange way in my opinion because I'd assume that meant they were the same everywhere, which is what I interpret as the meaning of the word global. Maybe there's scope for another category of database field for truly global fields.