have you tried looking on their site? kconusa.com should have the tickets available to buy. you will need to register with their site.
last year convention tickets were separated from the concert tickets but i think they are combined this time around. you should be able to purchase just convention tickets though too. id not on their site then at the convention itself. Where at, im unsure because set up is different every year.
there is a contact page on their site you could email. they respond very quickly.
if kevin is doing a meet and greet then there ia a high chance you will need to talk to other attendees in order to get a pass. the tickets for meet and greets are random lottery and only certain tickets get them. i believe it is p2 and above will get the chance for those.
hopefully this helps a bit. but it is best to reach out to kconusa directly. they are pretty great 😊 best of luck!