Experimental platforms are critical in proving the viability of new ideas, assessing diverse design assumptions, and qualifying choices to support technologies and services for future-generation wireless systems. This paper presents the design and implementation of an end-to-end (E2E) next-generation research platform using the open-source modules obtained from O-RAN Software Community (OSC) and OpenAirInterface Software Alliance (OSA). We first summarized the key issues and challenges in establishing and maintaining the research platform. We then elaborated on possible options for open-source integrating technologies and components, test tools vendors, and commercial products in developing the research platform. Finally, we highlighted the new results and lessons learned in developing and operating the research platform.