Some people say that I can catch ho-oh in the celestial tower I am not sure How I can do this I already tried but nothing happened is this a glitch or what
Those people were wrong. Besides the use of PokeTransfer and trading, Ho-Oh cannot be caught in a Black and White 2. So no glitch.
No, that's just a rumour. You can only get it by PokeTransferring it from HeartGold or SoulSilver. Sorry.
Hope I helped. :)