What have you tried so far? Feels like this should just work:
let dataset = createSolidDataset();
let thingB = createThing({ name: "ThingB" });
thingB = addUrl(thingB, rdf.type, "https://example.com/TypeB");
let thingA = createThing({ name: "thingA" });
thingA = addUrl(thingA, rdf.type, "https://example.com/TypeA");
thingA = addUrl(thingA, "https://example.com/uses", thingB);
dataset = setThing(dataset, thingA);
dataset = setThing(dataset, thingB);
(Edit: fixed ;
.)