You need to use a proper brush(es) to apply that eyeshadow rather than those rubbish applicators that come free. And fingers are only really useful if it’s a cream eyeshadow whereas the Chanel ones you’ve bought look like powders? You need a more delicate touch for powders so you don’t apply too much plus blending is easier with a decent brush.
Then just follow Chanel’s own suggestion on your link:
• To illuminate the eyes, apply the silver-toned dark purple shimmer to the middle of the eyelids, then add a hint of the blue shimmer highlighter to the inner corners.
• To intensify the eyes, apply the matte blue-grey shade to the eyelids, then layer the satin lavender shade on top to create an ombré effect. Blend from dark to light, working from the lower to the upper edge of the eyelid.
I use Trish McEvoy brushes for eyes (I have done for years) but there are lots of brands to select from these days.