Short answers, pulled from the story.
The brothers Asanga and Vasubandhu systematized the doctrines of Yogacara in the 4th and 5th century CE. While some believers attribute the origins to Maitreya, historical records point to the practical work of these two philosophers.
Yogacara centers on the concept of vijñapti-mātra which translates to consciousness-only or mere representation. This doctrine states that there is no separate object outside the mind because all images are mental representations.
Yogacara expands the traditional six consciousnesses into a system of eight bodies of consciousness. These include five sense-consciousnesses plus mentation and two deeper layers known as kliśtamano-vijñāna and alaya-vijñana.
Yogacara was imported to Tibet by Shantaraksita in the 8th century and to China by Xuanzang in the 7th century. These figures facilitated the spread of texts across regions where they continue to influence Buddhism today.