How to upload to Instagram

There is a giveaway contest on the internet and one of the requirements to enter, is to post a picture of the watch to your instagram page. I am unable to do this despite numerous attempts to do so. I asked the contest but was told that I should do it the same way that I posted the other three pictures on my instagram page. However those pictures were uploaded from my cell phone and not from my desktop, entirely different. So does anyone know how to get an image from the desktop to my instagram page ? People say that it is a very simple procedure, copy and post but you know the saying "easier said than done" lol

The lack of any reply means, that it is likely not possible to do this. Instagram was designed to be used with a cell phone and not a computer. So how am I supposed to be able to do this , when even in a computer forum no one knows how. Let them keep the watch, I don't really like it anyways but just thought it is nice as a status symbol because it is expensive. Probably thousands of people entered the give away, so not much chance of winning . Not worth spending my time and effort on this matter.

From what I'm reading its possible but sort of difficult. Instagram is designed for mobile not desktop so you need a work around.

https://www.google.com/search?client=firefox-b-1-d&q=how+to+upload+pics+from+pc+to+instagram

Some articles there on what you need to do.

Or if you have a phone, you can always transfer image from pc to phone then upload to Instagram.

From what I remember, you can only post photos on Instagram using your smartphone. Accessing Instagram website can only offer you little such as browsing your feed, tweaking your settings, and deactivating/deleting an account.