It really depends on how you are doing your development. Some people prefer Visual studio, others prefer the command line.
If you are using Visual Studio, select your project properties. Expand Linker, Select Input. In the dialog, under Additional Dependencies, add dfor.lib. Click OK to close the dialog, rebuild and that's it. Remember to do both Debug and Release.
If you are running it from the command line, just add dfor.lib to the link line.