"Sequence" is defined as "an arrangement of two or more things in a successive order" (Collins Dictionary). In reference to "plot," sequence means how events in the plot complications, conflicts and resolutions are arranged in successive order, one after another--or--in some works, NOT one after another as a result of flashback and flash-forward or modernist fragmentation. Let's look at sequence in relation to "Contents of a Dead Man's Pocket."
This is a suspenseful story told in chronological order with the inclusion of potentialities, if Tom should slip, in the form of mind's-eye flash-forwards: The events Tom sees in his mind's eye are not real, though he sees them as though real.
[He] felt his balance leaving him. He saw himself falling with a terrible speed as his body revolved in the air, knees clutched tight to his chest, eyes squeezed shut, moaning softly.
Out of utter necessity, knowing that any of these thoughts might be reality in the very next seconds, he was slowly able to shut his mind against every thought but what he now began to do.
The plot sequence, or sequence of events in the plot, begin at the beginning and go through his adventure (he might say misadventure)--including flash-forwards--and end with the resolution. The conflict of Self against Self and the theme of self-realization are built up and dramatized through the building sequence, which also builds suspense.
Briefly, s synopsis of the sequence is that Tom is working and, feeling hot, opens his stubborn window. His wife leaves for a movie while he stays home because he "has to work" (not strictly true ...). When his wife goes out the front door of their flat, the gush of wind from the door joins with a gust of wind from the open window to drag the all-important yellow paper out into the night high above the city streets below. Tom goes in search of his paper and nearly loses his life. As a result, he comes to have a new regard for himself and his wife and his work. Of course the details of the adventure are left out of this short synopsis, yet this still successfully illustrates sequence in reference to plot with "Contents of a Dead Man's Pocket" as an illustration.