If the publication's first author is a non-NTU staff, should the NTU co-author uploads the publication onto DR-NTU?

According to NTU Open Access Policy, all NTU faculty and staff are required to submit their papers to DR-NTU for open access, no matter whether he/she is the first author or not. But if you have some prior agreement with other parties that prevent you from submitting to DR-NTU, you may exempt it from submission. Even if there are no such agreement, it is still a good practice to check with the first author to alert him/her that the paper will be submitted to DR-NTU to meet NTU's open access policy. You can get more information on paper submission here (https://libguides.ntu.edu.sg/drntu/information).