To create a festive party atmosphere, decorate using balloons in a variety of colors, or choose one or two of your favorite colors. Attach streamer, and leave them to float. For an elegant look, use a tablecloth with a pretty pattern. You can also set a vase with flowers on the table. Leave the guest of honor to select the music.
'Attach streamers,' [what is it?]
Streamers are brightly coloured paper ribbons.
My suspicion is which one of the following pairs is idiomatically correct?
1a.Leave them to float.
1b. Leave them floating.
2a. Leave the guest of honor to select the music.
2b. Leave the guest of honor selecting the music.
Mind you: a gerund, in one sense, is also a verb, so do the present and past participles.
Btw, what do you mean by using balloons?