Figuring out that Alliance Roulettes are there is very simple and acting like a new player wouldn't be able to is reaching levels of condescension, it is a very simple process:

New player notices blue quests are different from the normal grey ones
>From the blue quests you are actually required to do, they understand that blue quests universally unlock *something*, very often a new instance.
>>New player learns that there are these large scale 24 player raids from the story requirement to do Crystal Tower.
>>>New player creates the expectation that they should be doing blue quests if they want more unlocked instances, a player who is interested in trying every content in the game will do them as soon as they are able.

Games should not masticate everything for players, and a bare minimum of deductive reasoning should be expected.