How to go about adding half sisters online that you've never spoke to before?

[Sarah]

So my birth mom told me today the names of my half sisters and gave me their facebooks. I want to add them online but I'm not sure how to go about it what to say, if its crossing some boundry. I'm not sure if they even know about me. I don't think they are even living with my birth mom. Anyone else have to do this before or have any advice? Thanks

[Lauren]

I've been in the same situation, do NOT add them. Send them a message explaining who you are and wait for a reply, don't randomly add them. I was in the same situation but with my father and my half sisters and I messaged him first then when he reciprocated , they all added me. If you just add them, they will think your just some random person, they wont understand and it will go down like a lead balloon.. Tell them who you are first and wait for their reply. If you don't get one then don't add them.