Senior Developer Guide Beginner [on hold]

I would like to seek some help. I became a senior developer of a team recently but I guess I struggled to start for it. I understand the business but how to implement it to a development team is another issue. Is there someone can give a guide on how to handle a development team and how to make individual member work on module independently on others. How can I split the program into modules using Laravel? I researched on laravel module library but looks like there will be a lot of files to maintain and depth of the code hierarchy as will seems bulky as I can imagine. Is that ok?

Thank you.