How long and in what way were the eggs stored before you set them? were they from your own chickens?
I believe i see veins on the egg, if it were not fertile, you will see the yolk moving around, and not the half light / half dark. It’s half light and half dark because a few days into incubation, the yolk breaks its round shape. So it definitely developed/is developing. Honestly, you might not see much on day 6, maybe a small moving embryo and veins. But sometimes eggs are hard to candle, especially porous and darker ones! Give it a few more days and see if there is any change. If anything, you should see the air cell growing and the inside getting darker.
Most embryonic death occurs in the first and last few days of incubation. are your thermometers and hygrometers calibrated? i would have another calibrated thermometer in the incubator you can check your readings against. Day 1 doesn’t start until 24 hours after you set the eggs, so if you set your eggs on Monday, that would day 0 and the following monday will be day 7.
The clear part is normal - it’s the albumen