>If the user chooses only (1), print lines type '00 '
>If the user chooses only (2), print lines type '01 '
>If the user chooses (1) AND (2), print lines type '00 ' AND '01' AND '011'

You should bind the checkboxes that your user clicks to some form properties, like .lIncludeDetails, lIncludeTotals, lIncludeSeparators... then in the code that reacts to the changes of these values,

lcList=""
select MyGridsAlias
if thisform.lIncludeDetails
   lclist=lclist+["00 ",]
endif

if thisform.lIncludeTotals
   lclist=lclist+["01 ",]
endif

if thisform.lIncludeSeparators
   lclist=lclist+["011",]
endif
lclist=trim(lcList, ",")
if empty(lcList)
   set filter to
else
   set filter to inlist(cFilter, &lcList)
endif
locate

Then refresh the grid.