Unfortunately, ResearchGate does not have an import function for users. However, several of your publications may be already available in RG, you just have to to confirm your authorship to assign these to your profile (see https://help.researchgate.net/hc/en-us/articles/14293005132305-How-to-add-research). To find such publications, you may do the following:

1. Look into https://www.researchgate.net/profile/Adigun-Oluwaseyi/unconfirmed (accessible only to you).

2. Search with the titles of missing papers in https://www.researchgate.net/search.Search.html?query=&type=publication.