docs: add instructions explaining library import

README.md

@@ -1,7 +1,5 @@
-
 ![Tapen Picture](https://raw.githubusercontent.com/corvis/tapen/master/docs/assets/cover-picture.png "Tapen cover image")
 
-
 <h2 align="center">Tapen</h2>
 
 <p align="center">
@@ -18,10 +16,10 @@
 </p>
 
 
-**Tapen** is a tool for composing and printing labels on label printers. At the moment only Brother printers are supported.
+**Tapen** is a tool for composing and printing labels on label printers. At the moment only Brother printers are
+supported.
 Developed and tested on linux only.
 
-
 ## Basic Usage
 
 Just print a line of text covering all available height of the tape:
@@ -54,15 +52,51 @@ There are a couple of possible installation methods:
 1. With pip: `pip install tapen`
 2. Use pre-compiled binary. Just download binary from [releases page](https://github.com/corvis/tapen/releases)
 
+## Usage guide
+
+### Libraries
+
+Library is a collection of templates to be used for printing. You can connect a library using `tapen import-lib`
+command. The general syntax is:
+
+```shell
+tapen import-lib <library-name> <library-locator>
+```
+
+Where:
+
+* `library-name` - name you will be using to refer to the library locally. You decide how you want to call the library,
+ however the name should be unique for your local installation.
+* `library-locator` - locator pointing the library. It can be a path to a local directory or a URL to a remote library.
+ The exact syntax depends on the storage. See below for details.
+
+There are a few library storages supported:
+
+| Storage | Locator syntax | Description |
+|-------------------|---------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------|
+| Local directory | `local:/path/to/library` | Path to a directory containing library files. |
+| Github repository | `github://owner/repo[@tag-or-branch]` | Github repository containing library files, **optionaly** you can include the tag or branch name. Example: `github://JointBox/labels@master` |
+
+Examples:
+
+```shell
+# Import library from local directory
+tapen import-lib my-lib1 local:/path/to/library
+# Import library from github repository
+tapen import-lib my-lib2 github://JointBox/labels
+tapen import-lib my-lib3 github://JointBox/labels@master
+```
+
 # Credits
 
 * Dmitry Berezovsky (@corvis) - author and main maintainer
-* Dominic Radermacher (blip@mockmoon-cybernetics.ch) - creator of libptouch, the source code of this library was used to understand the interface to Brotehr devices.
+* Dominic Radermacher (blip@mockmoon-cybernetics.ch) - creator of libptouch, the source code of this library was used to
+ understand the interface to Brotehr devices.
 * [CLI Rack](https://github.com/corvis/cli-rack)
 
 # Disclaimer
 
 This module is licensed under MIT. This means you are free to use it in commercial projects.
 
-The GPLv3 license clearly explains that there is no warranty for this free software. Please see the included LICENSE file
-for details.
+The GPLv3 license clearly explains that there is no warranty for this free software. Please see the included LICENSE
+file for details.