clone the repo and execute directly.Be sure you have already install Python (verssion > 3). 
       If don't then Install,
       
       Exmpl for deBased distro
       ~$ sudo apt install python
       or
       ~# apt install python
       ~$ cat req.txt | xargs pip3 install

                $ ./n3tool --help

                  N3tool (Network Enumetaing Toolkid)

                  Usage: n3tool [arg] <target>

                  Arguments:

                   -d   --dirs                   Files and directory enumeration [Broutforcing]
                                                 n3tool --dirs https://demo.com/ -w wl.txt
                   -e   --sub-domain             Subdomain enumeration           [Broutforcing]
                                                 n3tool --sub-domain target.com -w wl.txt
                   -m   --method                 Scan for alowed methods
                   -c   --check                  Print status of the target
                   -o   --output                 Dump output to the file
                   -s   --spider                 Spidering for header
                   -S   --spider-all             Spidering for header and get body to
                                                 output file
                   -w   --wordlist  <WORDLIST>   Specify wordlist to broutforce
                   -t   --time      <SECONDS>    pause the scaning time (Denote by seconds) FW-evation 
                                                 n3tool --dirs --time 0.5 https://demo.com
                                                 pause the scanning for every 1/2 second
                        --no-color               Ignore colors
                        --quiet                  Start without banner, and don't show status.


                  Examples: 

                  directory Enumeration:
                      n3tool --dirs --wordlist wordlist.txt https://example.com/

                  sub-domain Enumeration:
                      n3tool --sub-domain --wordlist wordlist.txt example.com