So, I opened Unity and in Tobii “readme file” was written that I have downloaded the Tobii Unity SDK for desktop version 3.0 Beta. I also had a file in my pc called CoreSDK-master which I think is the Tobii Core SDK and I removed it but still when I try to install in visual studio the EyeX.Framework it cannot be installed. I can send you picture for unity and visual studio in email if it is better to have a look.