The singular to plural rule basicaly is adding an "s" at the end of the word (p.e. rose-roseS) BUT if a two-syllable word ends in "-y" (p.e. babY) you add "-ies" (babIES). If the word is single-sillable (p.e. skY) you add "-es" (p.e. skyES) AND if you want to convert the word "woman"/"man" (which is SINGULAR form) to plural, you just place an "e" on the "a"'s place (p.e. womEn/mEn). I hope it helps :)

There isn't any rule of converting from singular to plural. You just need to learn the words by heart. Practice will help you memorize the words. Examples: ورقة - اوراق (paper/papers) وردة - ورد (ورود) (flower:flowers) There are exceptions to few words, but try first to learn as many words as possible. It will be easier for you to learn/memorize the exceptions later.

for the Feminine words you can just add "at" at the end for example : tawela - tawelat(tables) . But for the masculine words, there is no rule to use!