To your dotfile, add
(add-to-list 'org-latex-classes
'("frontiers"
"\\documentclass[utf8]{ext/frontiersSCNS}"
("\\section{%s}" . "\\section*{%s}")
("\\subsection{%s}" . "\\subsection*{%s}")
("\\subsubsection{%s}" . "\\subsubsection*{%s}")
("\\paragraph{%s}" . "\\paragraph*{%s}")
("\\subparagraph{%s}" . "\\subparagraph*{%s}")))