Is "Main Sequence" a temporal sequence?
No, the Main Sequence is more like a starting line. Most stars spend a long time on one point of it (10 billion years for the sun) while they fuse hydrogen into helium. Then they wander off it.

In this diagram the black line is the Main Sequence. The colored lines show temporal sequences. This progress through time of an individual star is called its evolutionary track.



The numbers along the black line are solar masses (1=the sun). This diagram evolved through a sequence of images by Wikimedia users Rursus, G.A.S, and Jesusmaiz.