Swift is a modern open source programming language that runs primarily on macOS and Linux. Swift was developed initially by Apple to interoperate with their key frameworks, Cocoa and CocoaTouch, both of which are mostly implemented in Objective-C.
Swift is influenced by a large number of existing programming languages, and it incorporates concepts from a wide range of programming methods, everything from scripting to object oriented and functional programming. Apple refers to Swift as a protocol oriented programming language and has expressed the goal of eventually making Swift useful for everything from scripts to an operating system.
This Swift Tour is an introduction the language.
A deeper overview of Swift from Wikipedia.
If you've downloaded the command-line client and have Swift installed on your machine, then go ahead and fetch the first problem.
exercism fetch swift
In order to be able to submit your solution, you'll need to configure the client with your Exercism API key.
exercism configure --key=YOUR_EXERCISM_KEY
When you've written a solution, submit it to the site. You'll have to configure the command-line client with your exercism API key before you can submit.
exercism submit PATH_TO_FILE