How to tell it's real labor

Hey ladies! So this is my 3rd kid but my first time going into labor full term. With my last two I just had period cramps to begin with and when I got to the hospital found out I was actually in early labor. My doctor had given me the go ahead and try to get baby out if I want so I'm gonna start walking extra sex EVERYTHING 😂. I'm not sure how to know when it's TRUE labor and I need to run to the hospital or when it isnt. Since I'm already 4.5cm dilated he said I most likely wont see a mucous plug or bloody and to just look for contractions or my water breaking. How long should I monitor contractions and how far apart before going in? I dont want to rush to the hospital for a false alarm but I also dont want to wait to long b/c I'm terrified of having the baby in the car on the way to the hospital 😂. What pattern and how long should I look out for the contractions before I guess its officially too late?