Rebuild a Website Header within phpBB forum

The job is to rebuild a websites header (Laravel website using Bootstrap as CSS framework) for phpbb (phpbb 3 newest version, prosilver_se theme). Since the bootstrap framework cannot be applied to prosilver_se without destroying this forum layout the classes have to be rebuild in order to make everything look the same. Same goes for the JS needed for the sticky white menu bar if you scroll down and the menus.

Check out the attached file for more details