Before taking full responsibility for a real classroom, pre-service teachers (PTs) can safely experience a rich learning atmosphere in a simulated virtual classroom environment and receive feedback on their lesson planning and teaching performance. This research aims to support and examine the process of structuring PTs' teaching skills with a multi-source feedback system integrated with simulation-based teacher training (SimInTeach-FBS). A phenomenological approach was employed in order to understand the nature of PT's experiences from a feedback system focusing on teaching skills. Seventy PTs, twelve mentor teachers (MTs), and six teacher educators (TEs) participated in the study. Various data collection tools were used to gain a deeper understanding of the participants' experiences: reflective journals, open-ended feedback forms, and observation notes. The results of the content analysis showed that teaching experience with SimInTeach-FBS raises self-awareness and improves PTs' teaching skills. It was revealed that teaching skills were mutually structured, feedback given to the PTs multiplied the effect of the development process, and teaching experience facilitated the transfer of acquired teaching skills to real life.