See this help page ("How to add research") for instructions how to add published or unpublished research to ResearchGate: https://help.researchgate.net/hc/en-us/articles/14293005132305
ResearchGate members can create publication pages for their content. If you create a publication page for your work, you are completely in control of it. You can edit it at any time, add or remove a full-text, or delete the page entirely.
You can add all kinds of work to ResearchGate, such as conference papers, preprints, or even negative results. Adding a variety of research is a great way to gain exposure for your work. More exposure leads to more feedback, collaboration, and sharing amongst experts.
To add a publication page to your profile:
Click the Add new button at the top right-hand corner of any ResearchGate page
For published work, select Published research and then the publication type
For unpublished work, select the most applicable type of research from the options shown
Follow the steps for the specific type of research you choose.
Note: When creating a publication page for some types of research (e.g. code), you are required to add a file. You must always make sure that you have the right to upload any file to ResearchGate before doing so. You can find more information about this in the Copyright section in the Help Center.
If the research you want to add does not fit into one of the available categories, you can still add it by selecting Published research or Other and then clicking the blue Add new format button at the bottom of the list. Research in this category will be labeled as Research and automatically assigned the upload date.