The pauses in the liturgy are part of the liturgy.
Arrive a few minutes early and say nothing. The silence before Mass is the first part of it.
Keep the pause after "Let us pray" before the priest continues. He is waiting for you to actually pray.
Keep the silence after the readings, after the homily, and after Communion, when the Church expects the longest quiet of the whole rite.
God is not loud. The whole tradition of Christian prayer, from Elijah at the cave to the Carmelites, holds that the decisive things happen under the noise. A liturgy without silence gives you no room to answer what you just heard.
Silence is not a modern austerity. Monastic and cathedral liturgies both built pauses into the rite, and the reformed Missal of 1970 wrote them back in explicitly after centuries in which they had been filled with music or private devotions.
The instruction is unusually direct: sacred silence is to be observed at the designated times as part of the celebration, not as a gap in it.
The pauses belong to the rite. What you do inside them is entirely yours.