Add basic usage info

Author: NamelessOne91

README.md

@@ -1,10 +1,27 @@
 ![Simple CI](https://github.com/NamelessOne91/bisturi/actions/workflows/simple_ci.yml/badge.svg)
 
 # bisturi
-Poor men's network analyzer
+A toy project network packet analyzer
 
 The compiled binary executable for bisturi will attempt to create a new raw socket and bind it to a network interface using syscalls.
 This will fail unless the program is run with root privileges, which is not advisable.
 
 You can use [setcap](https://man7.org/linux/man-pages/man8/setcap.8.html) to grant the binary executable *only* the capability to operate on raw sockets.
 This is the default behaviour of the included Makefile's **build** command.
+
+
+## Usage
+
+You can build the binary executable with the `make build` command.
+
+The following flags are available to customize bisturi's behaviour:
+
+| Flag | Type | Default | Meaning
+| :---:|:--:|:--:|:--|
+| i | string | eth0 | network interface for which the packets will be analyzed |
+| p | string | all  | protocl filter - 'all' equals to no filter |
+
+Running bisturi with the provided `make run` command is functionally equivalent to running bisturi with the following flags, which are its defaults:
+
+`bisturi -i eth0 -p all`
+