> For the complete documentation index, see [llms.txt](https://docs.langstack.com/welcome/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.langstack.com/welcome/get-started/learn-langstack/basics-and-essentials.md).

# Basics and essentials

**Take a walk-through of the key elements of Langstack. By the end of this section, you will have explored the basic building blocks for creating and deploying Langstack solutions.** 

In this section, learn to grasp the basic concepts of the following:

* API gateway
* Entities
* Action boxes and Actions
* Langstack Data types
* Variables
* Functions
* Type conversions.