How to attach a customized visual assist form to a field

For attaching customized visual assist needed to create are search and select form with required fields.

Now for attaching this form to required field follow the steps below:

   EVENT:  Visual Assist Button Clicked
-----------------------------------------------------------------------
     OPT: Using Defaults
0001 Suppress Default Visual Assist Form

-----------------------------------------------------------------------
     EVENT:  Post Visual Assist Clicked
-----------------------------------------------------------------------
     OPT: Using Defaults
0001 Call( App:P561234 , Form:W561234C )
        FC Project_v <> FI szCommunity
        FC Unit No_V <- FI szUnit

Call the form that is required and pass the data that has to be fetched