Bean,
1) Saw "red"
2) Water bag burst
3) labour pain
When u see 'red' or water bag burst, u can go and take your shower, get ready towel and get your husband send u to hospital liao.
For my case, when i had my #1, i dun have (1) or (2), i had (3), so wait until your contraction pain, count fm the start time until the next one come, if the interval is like 15 to 20 mins, get ready and go to hospital.