> How long will it take to reach them?

185 years at 0.2c [1][2]. (No deceleration at the other end.)

[1] https://hpf.psu.edu/2026/06/30/gj-3378b/#:~:text=Introductio...

[2] https://en.wikipedia.org/wiki/Breakthrough_Starshot#:~:text=...