Warning: These are non-official, there might be errors. Also, this would not have been
have been possible if I didn’t have access to my former tutor’s solutions
from 2019, when I took a similar course in Göttingen.
A full solution to Sheet 0 can be found on pages 6ff in Brüdern’s Einführung
in die analytische Zahlentheorie (german), or (in a slightly different form)
on the first few pages of Tenenbaum’s Introduction to analytic and
probabilistic number theory.