The YAML anchors to name a reusable section are defined by &name and then to use them to replace the value of something you do *name, if you want to “unsplat”/merge a dictionary/object then use <<: *name and then it’ll insert it at that point.

world: &world World
example: &example-anchor
  HELLO: *world
  There: Yo

my-values:
  <<: *example-anchor
  foo: bar

becomes

---
example:
  HELLO: World
  There: Yo
my-values:
  HELLO: World
  There: Yo
  foo: bar