Implanon help!! Sex??

Bobrdoodle • I'm not much
I'm on the Implanon and I just read about if you are outside of your period you are suppose to use condoms and other sorts of protections before you have your period so you are sure that the Implanon takes effect. 
But my GP doctor told me when she removed my expired Implanon and inserted a new Implanon that I was able to have sex right after because I inserted it straight after instead of waiting a certain amount of time. 
But since I read it it's made me scared because I can't risk it but I don't get my period on the implant so what would I be waiting for?
Can anyone help me with this?