Add this to your .vimrc
map gn :bnext<cr>
map gp :bprevious<cr>
map gd :bdelete<cr>
" I personally use <leader>
map <leader>n :bnext<cr>
map <leader>p :bprevious<cr>
map <leader>d :bdelete<cr>
Note that you are remapping gp and gd, but maybe you don’t care about that (:help gp, :help gd).
For more information on how to map key strokes see :help map-overview and :help map.txt.
Btw, I personally use <leader> instead of g in the mapping. My <leader> is set to ;. This puts my <leader> key on the home row which makes me willing to map all kinds of stuff using <leader>. :help mapleader if you want to change your <leader> key.