Weaver birds usually make their nest when they're looking for a mate. So in their juvenile years.
with stick and old grass brown grasss
Out of twigs, small sticks, feathers, leaves you know the usual stuff.
they cut off twigs, branches,leaves of trees with their claws. With spit, mud, and twigs... that is easy
Birds make nests so they can keep their babies safe. Also to have a home to stay away from predators. (which would be carnivores like hawks, voltures or other animals that eat birds.)