It is not recommended to download packages, you can get
with the 'Package Manager' = 'Synaptic'.
The command line can be used too :
sudo apt-get install <package> <package> <package> <package>
If you have no internet connection :
Downloaded packages can be "chain installed" :
sudo dpkg -i <package>.deb <package>.deb <package>.deb
... Then circular dependency isn't appearing.
Circular dependency is, when two or more packages
depend on each other.