What are the Catholic Church's instruction on kneeling down in prayer in churches?

In Catholic churches where pews are in place, one rarely notices the faithful kneeling down in prayer except perhaps during the Prayer of Consecration . In fact, in earlier times, the faithful would kneel down on entering the church and during a number of prayers of the liturgy. Of late, there seems to have come up some schools of thought advocating against kneeling in prayer. My question therefore is: **What are the Catholic Church's instructions on kneeling down at the church, by the faithful during the liturgy and otherwise.**