begin measure with rest

I apologize that this must be a completely foolish question, but I cannot find an answer to it in the manual or in these fora. The melody I am trying to transcribe begins with a few intro notes -- only three eighth notes, but I cannot find a way to get Musescore let me preface these with a rest. So, if I enter these, Musescore puts them into the nect measure, which screws up the placement for the rest of the song. Or, I can put them into the first measure, but then there is a rest after them, which is ridiculous. Any help? How can I insert or move a rest?