"They open at 11."
This sentence refers to an establishment opening for business (such as a restaurant that only serves lunch and dinner opening at 11am).
what is this strange character for men?? should be like that: 们 (remove the left part) Ok i can't write it correctly on their page? They use a strange font of character, feels like HK or TW one... Or maybe it's because i never type it down?
The character (traditional = 門 ,simplified = 门) means 'door, gate, opening' basically. It has other meanings, but those are the most common. It is spelled the same in PINYIN as 们. If you get a list of characters to choose from, when typing in PINYIN, it should be there.
Exactly, it might help to think of these as homophones, like bear and bare or pair and pear; 门 and 们 have nearly the same pronunciation (they do have different tones) but they have very different meanings. Also (like these) they quite often have some "structural" similarities.