|U need to understand that i have no control over main network and i don't even know who set it up|
Ok, this is rather important information and the kind of thing you need to post at the outset, not in your last post. We're not mind readers and both Paul and Wanderer have given you good advice based on what you told them.
and last of all - they don't want to change anything. So, i was trying to add to it without changing it :).
Considering what you said above, the next big question is, "How the heck can you add something if you can't make changes!?!?!?"
I'm afraid the two statements are contradictory. Either you can make changes or you can't and if you can't, then you can't add a guest network.
I suggest you talk to the person who can make changes and get them to create your guest network. If you'll pardon me for being blunt, you're obviously not qualified to do this in the first place so I have to wonder why you don't just get whomever is (ie: the person that set your network up to begin with) to add the guest network.