Repeat the Dec row and the one row following it. You’ll be decreasing on the odd number rows.
Both of these rows tell you to work in the yoke pattern.
So work row 1 of the yoke pattern with the dec in the last 3sts, then work row 2 yoke pattern, no decrease.
Work row 3 yoke pattern with a dec in the last 3 sts, then work row 4 yoke pattern, no dec.
Work row 1 again with dec and row 2 no dec. and so on.
Remember to take into account the fact that you’ve decreased sts. You want to keep the yoke pattern aligned with previous rows.