Can anyone tell me what is the procedure to start using the e-packet service? Can you just walk into the post office in China with your parcels?

Hi, i am planning to start selling on ebay and i live in china. So , i decided to use epacket as a shipping method but strangely when i went to china post it seems like they don't know about e youbao/ e packet service. I am currently living in xiamen and would like to know about the total procedure.