90. To the Concluding Rites belong the following:
a) brief announcements, should they be necessary;
b) the Priest’s Greeting and Blessing, which on certain days and occasions is expanded and expressed by the Prayer over the People or another more solemn formula;
c) the Dismissal of the people by the Deacon or the Priest, so that each may go back to doing good works, praising and blessing God;
d) the kissing of the altar by the Priest and the Deacon, followed by a profound bow to the altar by the Priest, the Deacon, and the other ministers.
None of this is terribly controversial. Regarding 90a, I’ve seen announcements placed between the gospel and homily, and also after 90c, the dismissal. Often they are located before the post-Communion prayer, presumably to give the people a chance to take them sitting down. In my mind, preferable would be to stand (if needed) for post-Communion, then be seated for announcements.