Translation:The book is not fun.
No, because there is a difference and that is for example if u want to say "cool", it is 멋었습니다 And u want to say "delicious" or "tasty", it is 맛었슴니다 If you can't see the difference, look at the second letter of each word, and then u can find what will make u look for a difference
Funny and fun arent the same, something funny might make you laugh but something fun probably wont, it will make you have a good time but not laugh, you cant call a joke fun or call and activity funny if you ment you had a good time with it. My explanation might not have been enough, so try searching their meanings and try comparing and contrasting
Yeah, 있습니다 (or 있다 in its infinitive form) means to exist or be present, while 없습니다 (or 없다 in its infinitive form) means to not exist or to be absent. So adding any noun before one of these verbs means that either that noun is there/present/extant or not there/absent/nonexistent.