In Travco, there are two ways to report incoming attacks. It is either manually or by copy-pasting your rally point.

Manual attack report

It is quite simple, you just fill in all the necessary info and hit "Save". 

Report attack through rally point

To report attack through rally point you have to go to the rally point, filter out incoming troops -> incoming attacks.

Then hit CTRL + A, that will select whole page. Then CTRL + C to copy that page. And CTRL + V into the text area at Travco.