Please note that ResearchGate is not a publisher and not a journal, you cannot publish a paper here. It is a platform for papers published in journals, or to present unpublished texts, data etc. See also "Is ResearchGate a publisher?" in https://help.researchgate.net/hc/en-us/articles/14292596164753. And see this help page ("How to add research") for instructions how to add published or unpublished research to ResearchGate: https://help.researchgate.net/hc/en-us/articles/14293005132305
If you mean to ask how to get your work/paper published, I suggest you might need to look for a journal which fits in well with your topic… I think this is always essential to have the best chance for your work/paper to be published.