first sign can be
having a show
waters breaking
contractions starting
ir just the contractions
or waters break and nothing happens
or you can have a show and nothing for a week, so it is all so different
but regular , rhythmic contractions, that increase in intensity, and the time between them diminishes, lasting around 1 minute, is a reliable indication on the whole!!
i would try and manage until contractions 5 minutes apart , or 3 !! as you are more likely then to be in established labour and dilating, or you might end up being sent home
also, at home, you can use, TENS, or water as pain relief, keep moving, active, mobile and not restricted..you can eat and drink as you feel you need to
you should call to let them know, and they will most likely advise when you should come in