Unfortunately, you can’t play Roblox on XBox 360, but you can play it on XBox One and higher models.
On XBox One, log into your Xbox with the Xbox account and download Roblox game from the store. It’s free to play and you don’t even need a game disc. But you do need Xbox Live Gold account and an Internet connection. Using a XBox controller is not as easy as playing the game on a mobile phone or iPad, but after a while, you do get used to it.