Question

what did guru Dronacharya ask his disciples to do? ​

Answer 1

After meeting Eklavya, Dronacharya asked him to introduce himself and also reveal the name of his Guru. Eklavya said that he is the son of Hiranyadhanus of the Nishadha tribal clan, who has allegiance to the Kingdom of Magadha.

Answer 2

ᴀɴs=He had already promised to make Arjuna the Sarvashreshtha Dhanurdhar (the best Archer). When he realised that the archery skills Ekalavya possessed were much better than Arjuna, he accepted him as a disciple and asked for his thumb as Gurudakshina (Teacher's payment). So that he is never to do archery again.