You have created an EXE project, not a DLL project. You need to pick one or the other.
From the Project window, go to Build >> Target Type >> Dynamic Link Library. You can use the Code Generator (Code >> Generate >> All Code) in the UI editor to create the shell of your program.
Create a .h file with prototypes for functions you wish to export. The functions may be declared similar to
extern long int DLLIMPORT MyDLLCdeclFunction(char * dummycharname);
From the Project window, go to Edit >> Add Files to Project... >> Include (*.h) to add your new .h file to your project.
Then go to Build >> Target Settings >> Change (in the Exports box). Select the .h file with the exported functions, then click OK.
Look at the sample programs that ship with CVI.
...\CVI\samples\dll\simple\cvi\readme.txt
...\CVI\samples\dll\simple\cvi\mydll.prj
...\CVI\samples\dll\simple\cvi\simple.prj