Necessary ports：/usr/ports/graphics/ImageMagick
/usr/ports/print/teTeX
/usr/ports/print/ghostscript-gpl
/usr/ports/print/dvips
Following the official wiki, install the plugins in the directory. It will be in dokuwiki/lib/plugins. After this, fix class.latexrender.php because the paht of the program is not the same as Linux system.
class.latexrender.php (line:36 – 39)：var $_latex_path = "/usr/local/bin/latex";
var $_dvips_path = "/usr/local/bin/dvips";
var $_convert_path = "/usr/local/bin/convert";
var $_identify_path="/usr/local/bin/identify";
If Latex won’t work, try this way:
https://b2.zeroplex.tw/2009/02/use-latex-in-mediawiki-in-freebsd.html