In ResearchGate, there is not so much you can do to increase the number of citations. Citations are identified automatically (see also my reply to https://www.researchgate.net/post/Why_so_many_of_my_genuine_citations_were_not_spotted_by_the_ResearchGate_citation_managers_Is_there_anything_I_can_do). On increasing the h-index, see my reply to https://www.researchgate.net/post/H-index_issues.
You will find some general recommendations in these discussions:
I agree with Dr Wolfgang R. Dick that there is little you can do in RG to boost your h-index. In general, to increase h-index, I have found the most useful technique is to discuss research ideas with other people with interest in those topics. I might encounter them at conferences. Unfortunately, this is a slow process for increasing h-index.