you should leave the type as keyword
the keyword criteria has settings for the Or Separator, the And separator and the start / end encapsulator.
these settings effect how you should enter the search terms.
the default settings are:
Keyword AND separator: ", " <- comma followed by a space
Keyword OR seperator: " " <- a space
Start Encapsulator: " <- double quote
End Encapsulator: " <- double quote
this would mean searching for:
foo bar
would look for foo OR bar in the record
foo, bar
would look for foo OR bar in the record
"foo bar"
would look for the string "foo bar" in the record
