Securing the Talent is a level in the fourth hub world Gilly Island. There are five big diamonds you need to collect (as opposed to six in the original game). Collecting the small pink diamonds is also necessary, so descriptions for those have been added. Also, you'll probably get these naturally as you complete the level, except for maybe the invisible one.EDIT:
I didn't realize the video only had locations for 3/5 of the big diamonds needed, so I've updated the solution with some helpful screenshots from PowerPyx
1) On a shell, on your way to letter “Y.”
2) During the Yeti level.
3) On a red, moving platform by speaker 3.
4) On the area above the level start, near the chest, on a small ledge to the right.
5) This one is invisible and is on a ledge near the letter “Y.” The ledge can only be reached from the area above the level start (where you’ve picked the letter “U”).
For the small pink diamonds: I believe there are only two, and both are right next to sets of speakers you are required to break to complete the level (if anyone finds additional pink diamonds, please leave a comment with the location).
1) On top of the patio by the waterfall where Lady M sends a group of enemies to attack you. It's right between the speakers you must smash after completing that battle. Note: this is also the area you'll need to be to jump to the invisible big diamond.
2) On top of a pillar, right behind the speakers, that you must get to by crossing the unstable platforms that sink when you step on them.
Personally, I got all of the diamonds naturally except for the invisible one which I couldn't find until I used the below video. Unfortunately, this video only shows where to find three of the five big diamonds - but it includes the invisible one, which is a bit tricky to locate if you don't know where to look. Not my video, credit to Brick227
for posting this to YouTube.