IGTV is a new App, it can be use alone and its now integrated with Instagram.
Its a new feature and it allows you to record up to an hour long video and upload them and share them on this platform. its like Instagram linked with youtube
Because its now integrated with Instagram , it means your followers will be notify about your new videos or your new videos will be shown to their IGTV news feed. you can create your own channel acording to your videos type.
if you want to record a new video you will have 2 options like this, either to upload it on Instagram or IGTV channel.
you can check newsfeed of IGTV by clicking on top option on newsfeed page like this
when you click on IGTV option you will get a welcome note like this
you can check videos of every category like videos of following people , popular videos like this