When you just go on the instagram website on your Chrome browser, its default to something like this
Press F12 on your keyboard, and you will be shown this freaky panel on the right side. Click that blue icon to view the site in "Mobile Mode."
Ok, almost there. Now you just need those buttons at the bottom like what your phone has.
Refresh the page or press the F5 button on your keyboard to reload the screen, and viola, the mobile buttons show up.
Now you're pretty much where you need to be. It wouldnt make much of a difference, but if you can also change the view for each mobile device also by hitting the arrow down button where it says "Responsive."
Then you can choose other devices you want to view the app in. It doesnt only work for Instagram, but i figured it would be a good place to start.
This is almost all the features, that mobile has, however, there are certain things you cant do:
You cant live stream off your computer's webcam.
You cant upload albums.
You cant upload videos.
You cant do filter. (seriously, you have other software.)
Uh, thats about it...
But you can refer your friends to this site for a guide to do something kinda cool like this.
Follow me please? xD