1. Opening through FireDAC interface. Select FireDAC interface, click Informix, then fill all needed database parameters.
2. Opening through ODBC DSN (interface: ADO or BDE). Select 'ODBC data source' option and then select the ODBC DSN from the drop-down list. But first, you should create an ODBC DSN of the corresponding type using Windows administrative tools, and point it to the database.
3. Opening through connection string (interface: ADO). Select 'Connection string' option and write a connection string. This way is the most flexible one because it allows to specify many additional parameters in the connection string and override standard Exportizer connection behavior. But it is recommended basically for advanced users. Here are basic connection strings (more examples and details can be found in the Internet):
Provider=Ifxoledbc;Data Source=dbName@serverName;User ID=myUsername;Password=myPassword; (IBM Informix OLE DB Provider must be installed)