Switching & Routing Lab Q# 7 & 8

I need clarification on how to complete Q# 7 & 8
for #7 did try sudo ip addr add dev eth0
Is there something I am missing? Is there another command that needs to follow?

#8 Entered:
sudo ip route add via
sudo ip route add via
Not working???

Also, in #6 how does it know to replace the new ip addresses with the old ones as we are not specifying which belongs to app01 - app04. How does it know which ones to replace?
How does it remove old ip addresses assigned? is it just over written???

It’s an initial problem in the lab and we are still investigating on it.