Please note that ResearchGate is not a journal and not a publisher, you cannot publish a paper here. It is a platform for papers published in journals, or to present unpublished texts, data etc. See "Is ResearchGate a publisher?" in https://help.researchgate.net/hc/en-us/articles/14292596164753. See also this help page ("How to add research") for instructions how to add published or unpublished research to ResearchGate: https://help.researchgate.net/hc/en-us/articles/14293005132305