change the icon, capx attached?

in the project file in the right side you should have a icon folder, and inside the icon folder there will be icons, you need to replace them accordingly to their initial size, the loading-logo can be anything you want as size.

for C2 the icons are inside the file folder.

Yes, the icons have default sizes already made, you have to convert your desired images to those sizes, or import a 512x512 image and convert it to the default size in the icon folder, for the icon /favicon u need a 32x32 and a 16x16 image.

Dev, is painful lol ... im stuck at a webgl effect which is like 50% gameplay visual effect of the project im working on.