An object is what receives the action of a verb or verbal. It is always in the objective case (in English) or accusative case (Greek, Latin, etc.). An object is always found by asking "what?" Verbs, infinitives, participles, gerunds and prepositions can all take an object. video
Ask yourself..."Jeb built what?" Jeb built a house. Hence, "house" is the object of the verb "built".
In Hebrew, an object is often indicated by the particle את; see here.
The IO (or “indirect object”) will be found between the verb and the direct object. If there is no direct object, then there can be no indirect object. The indirect object can be found by asking “to whom” or “for whom”.
Here are the analytical questions to ask: The verb is “built”. Who is doing the building? Jeb is doing the building. Therefore, “Jeb” is the subject. Jeb built what? Jeb built a house. Hence, “house” is the direct object. Jeb built the house “for whom”? For “Joe”, so “Joe” is the indirect object.
An indirect object will be in the dative case. (BBG 7.6)
A noun functioning as an indirect object will have the lamed preposition.