When reporting about or from Myanmar, it is no longer necessary to say at the top that it is "Myanmar, also known as Burma," as our style has been since 2011. We feel there are very few in the audience who still need that immediate reminder.
It is also no longer necessary to include the reminder about the name Burmain every report. Use your judgment. In longer pieces, and especially in those tracing the country's recent history, an "also known as Burma" is appropriate and helpful.
Meanwhile, our guidance (and AP's) has been that Myanmarese is the adjective to use when describing the people of that country. You should know, however, that there is disagreement over whether that is the proper adjectival form and that people in Myanmar do not refer to themselves that way. Many authorities say Burmese is the word to use, even when referring to the country as Myanmar. One way around all that, of course, is to say something such as "the people of Myanmar" or "the people here."