Cant download irishaders

Whenever I try to download it (it has been like this for like a year, I have never been able to actually download it) it says I need to pick an app to download it in. It's like it doesn't recognize any java files to download the irishaders onto or something? I have multiple times tried to delete every java and Minecraft file on my pc and reinstall it. I have looked through the hole thing and it still dosn't work. I would really appreciate some help with this issue so I can start downloading. I will put in some screenshots as well.