The context define all the already discussed property for types :
You can use the "Link" header to define the context of your request when calling the NGSILD-Broker.
<https://sedimark.github.io/broker/jsonld-contexts/sedimark-compound.jsonld>; rel="http://www.w3.org/ns/json-ld#context"; type="application/ld+json"
An example of asset creation for a broker deployed on "localhost:8080" would be the following :
POST "localhost:8080/ngsi-ld/v1/entities"
body : example here