no sé por dónde empezar

I don't know where to start

→ no
phrase Rare #40,535
I don't know where to start Used when someone feels unsure how to begin, often because there is a lot to say or do. It can also be adapted to other subjects, such as “no sabemos por dónde empezar” (we don't know where to start).
SP: Hay tantas opciones que no sé por dónde empezar.
EN: There are so many options that I don't know where to start.

Tengo tantas cosas para decirte que no sé por dónde empezar.

I have so many things to tell you that I don’t know where to start.

No sé por dónde empezar.

I don't know where to start.

Tengo tanto que hacer que no sé por dónde empezar.

I have so much to do that I don't know where to start.

No sé por dónde empezar, Cristina.

I don't know where to begin, Cristina.

— La piel que habito (2011)

Tengo tantas cosas que decirte que no sé por dónde empezar.

I have so many things to tell you that I don’t know where to start.