when I use system pre-installed vim and want to change the highlight, terminal told me "vim/vim90/syntax/syntax.vim" can't use, so I opened the directory"vim/vim90" and found that there are no son-directories(I reinstall vim, there should many directories normally)

maybe there are some wrongs in pre-installed vim?

I'm new in BSD, I just found that there are many differences between tutorial and my directory, maybe I don't know how to use pre-installed vim correctly.
Best wishes!

GhostBSD comes with vim-tiny preinstall. You can replace it with vim.