I also Korean beginner. So, sorry if my answer can't satisfy you. As far as I know, 네요 is a ending sentence. Usually we use it if we want to express our impression, thought, or surprise. Example:If you've ever watched a movie and you want to tell to your friend that the film is interesting, you just say 그 영화 재미있어(요). But if you are watching a movie right now and for the first time you watch it and according to your opinion the film is interesting, you feel surprise, so you can say 그 영화 재미있네(요) - usually if we talk with our close friend, we don't have to use 요, it is called 반말.

세요 or 으세요 is a ending sentence to which is used when we talk to senior about senior but in informal situation. I think (으)세요 comes from 시/으시 + 어 + 요 and (으) 시 is honorific marker, if the subject is older than you or you respect him/her, you can show your respectful by adding (으) 시 after the verb stem. But if you talk to junior about senior and in informal situation, you can omit 요, and because 시 + 어, the result is (으) 셔. If the verb stem ending with vowel, add 시, and if the verb stem ending with consonant, add 으시. Example:you talk to your friend about your mother (talk to junior about senior in informal). My mother goes to the market everyday - 우리 엄마께 매일 시장에 가셔 (가 + 시 + 어) - 가다 = to go. But if you talk to your uncle/aunt about your mother (talk to senior about senior in informal). My mother goes to the market everyday - 우리 엄마께 매일 시장에 가세요. You can politely ask to someone by using this form too, 우리 엄마께 매일 시장에 가세요? - Does my mother go to the market everyday? It depends on the intonation. (으) 세요 also can be used for imperative sentence but less formal than (으) 십시오 (more formal). Wait for a moment = 잠시만 기다리세요! Example if you say to your younger brother to study, you can say 공부하세요! For 가네요 maybe if you are surprise that someone has gone, you can say with 가네요. I forgot to tell you about (으) 세요. Mr Hoon remembered me that this form also can be used to ask someone to do something politely, example: Please give me a bottle of beer = 맥주 한 병 주세요. And for 가세요, Mr Hoon also remembered me that if there is someone want to go and leave us, we say "goodbye", we usually use "안녕히 가세요". Only this that I know. I hope my answer can help you.