How do I learn to play guitar sitting at home?

For beginners. Get a strong internet connection, Follow different guitar tutorials on YouTube. That is going to give you basics of guitar and music and can get you going for the time being. But sooner or later you should be joining private/group sessions with an experienced teacher who can make you learn in a fun way. 

Listen to guitar cover songs and listen to all types of music. 

Don't buy on a cheap guitar just for the sake of starting out. You'll easily get frustrated and will probably stop learning guitar after a few weeks. Instead invest in a good quality guitar. Yamaha offers decent base model guitars that'll work just fine for beginners and will keep them engaged in learning. 

Happy practicing. 

Firstly start with some basic finger exercises that will built your fingers to use on fretboard more smoothly. Then get some knowledge about the scales (atleast Major and Minor scales). So that you get a little bit of idea how things starts and work on guitar. Then start learning Chords and Strumming Patterns. Then some chords combinations. It will take some time to get balance or rhythm on the hands. So be patient on that. Then start covering some songs so that you will get idea how to sing while playing guitar. But don't just stuck on the songs. Start improvising on the scale. You can use backing tracks of drums or any other instrument. The improvisation will play a key role in your creativity. Then learn some new techniques or approach to play the same things but in different styles. They most important thing is consistency. You have to be consistent and you have to practice with discipline. Avoid distraction like using phone while practicing. And also start listening to some guitarists. It will give you new ideas and improve you a lot. Because listening good music is as much important as our practice. I would like to suggest you that you should join classes and atleast clear your basics from a good teacher or mentor. It will give you atleast basic understanding of the guitar or music so you can continue with some things on your own as well.

All the best!