Much like other additions (more AoY than that one Kelvin mission) it’ll be mostly contained within itself, at least up to the point of its release, afterwards we’re likely to see more distinct DIS episodes/missions come along as the show itself does, but still with other episodes/missions being produced.
It is not in the Prime Timeline, no matter how much they insist that it is. We have seen the Prime Timeline in what is about a decades time, in all depictions it has been as TOS was styled. Scotty’s Enterprise, the nil, as seen in Relics (TNG) was as it looked on TOS; the Defiant went back in time to K7 as of The Trouble…
They can insist all that they wish that Discovery is in the Prime Timeline but it shall never be. The only reason I'm going to be making a new character is to kill the Discovery klingnots and get whatever bonuses/unlocks I can for the ONE character that I do play with any regularity.