Just as whenever you collaborate with a brand, you also need to disclosure your relationship to the brand when you receive products for free or are gifted something. Please make sure to follow your regional guidelines and make sure to mention both verbally and with text whenever you promote a product you received for free on any of your social medias.
The disclosure needs to be clear, ideally in the beginning so it's visible and clear.
During a live stream it's good if it's repeated so that new viewers are informed.
Here are some examples that could be ways of doing a disclosure of a gifted product:
Ex: "I was gifted this product..."
Ex: "I'd like to thank @brand for giving/sending me this..."
Using hashtags like #gifted, #ad or #sponsored (and not hiding them)
Explicitly stating (via caption and/or video) that you have received a free product.
The idea here is simple: there should be no doubt.
Read more about the general disclosure requirements HERE.