Maitreya is the manifestation of all the Buddhas's realization of loving kindness.  His function is to guide us along the stages of the path to enlightenment. 

When he appeared as one of Buddhas' Shakyamuni's main disciples he was called 'Bodhisattva Maitreya'. 

In truth, Bodhisattva Maitreya and Buddha Maitreya are different aspects of the same person. 

Through relying upon Buddha Maitreya with faith we will receive this Buddha's special care, and he will bestow upon us the realizations of Kadam Lamrim through which we can solve our own and others' wishes.