The gerund or present participle is one of the non-personal forms of a verb. Its main function is to form the perfect tenses together with the auxiliary verb "estar" (to be, as an auxiliary verb).
1st conjugation -AR: participle ends in -ando
2nd conjugation -ER: participle ends in -iendo
3rd conjugation -IR: participle ends in -iendo
1st conjugation -AR: participle ends in -ando
2nd conjugation -ER: participle ends in -iendo
3rd conjugation -IR: participle ends in -iendo