Install from source using:
pip3 install scapy-python3 for latest published package version.
On all OS except Linux libpcap (winpcap on Windows) should be installed for sending and receiving packets (not python modules - just C libraries). libdnet is recommended for Darwin, FreeBSD, Unix. Windows does not require libdnet. If running into issues with routes and interface detection, netifaces module installation can sometimes help, but otherwise is not required.
N.B.! As a difference from scapy for python2, use bytes() instead of str() when converting packet to bytes. Also, most arguments expect bytes value instead of str value except the ones, which are naturally suited for human input (e.g. domain name).
You can use scapy running scapy command or by importing scapy library from interactive python shell (python or ipython). Simple example that you can try from interactive shell:
'www.somesite.ex' as a string, and
b'Some raw bytes' as bytes. Domain name is normal human input, thus it is string, raw packet content is byte data. Once you start using, it will seem easier than in looks.
Use ls() to list all supported layers. Use lsc() to list all commands.
Additional examples in API documentation
All commands listed by lsc() should work. Tested layers are:
Currently, works on Windows (8/2012 and up), Linux, Darwin, Unix and co. Using python 3.4 on Ubuntu and FreeBSD for testing. Using Windows 10/Anaconda 3.5/WinPcap 4.1.3 for testing on Windows.