title: R Caret's timeslices - window and horizon unclear
body: <p>Using the timeslicing in caret, and it's parameters,
  how do I split up data with xyz rows with each having a length of 12?</p>
  
  <p>Ideally, also considering the 60-20-20 train-test-validate ratio.</p>
  
  <p>Should I set it like so:</p>
  
  <p>initialWindow=12, horizon=12, fixedWindow=TRUE?</p>
  
  <p>I've read the documentation but this is still unclear to me.</p>