How do i install mob skins?

(Sorry if its obvious but i googled it and couldnt find anything)



So the site says to drop a zip into the resourcepack folder but when i download, its a png, and mc doesnt accept that so i have no idea what to do.



Also, is there a way to convert or use bedrock mob packs for java? i really wanna use this radish fox skin but i cant :(



If you can help me in anyway, id appreciate it!