Open FL Studio
Import the one-shot audio file into the Browser or Playlist
Drag the one-shot into the Channel Rack or Playlist
Open the Channel settings for the sample
Adjust the root note if needed
Set the time stretching mode if needed
Use the Piano Roll to trigger the one-shot with MIDI notes
Adjust the envelope settings if you want the sample to stop or sustain differently
Use the Mixer to add effects or route the sample to a track
Save the project when finished