DO and QF populating select options

Hi This should be easy - everything I've read says so, but I cant get it working. I have a DataObject that references another table via a foreign key. The relationships are set up in links.ini. I can factory the second table and retrieve the query, eg id and name which will be the select options, but I cant work out how to then insert the result into the QF select element options. Sorry this is such a dumb question. I've read, looked, tried everything I can think of and I know it shouldn't be difficult but... Please advise. Thanks Prue