OK, so I don't know how you have your picture files set up, but I'm going to assume you have it the traditional way with the title screen background being a parallax and the options being their own separate pictures. If that's the case, it's very simple to manipulate. Basically, you have it set up like a normal menu where you have a variable that increases by 1 whenever you go one way and decreases by 1 when you go the other way. Here is something like how it would work.
Conditional Branch: menu < 3
Conditional Branch: Input.isTriggered('right')
Control Variables: menu += 1
Branch End
Branch End
Conditional Branch: menu > 0
Conditional Branch: Input.isTriggered('left')
Control Variables: menu -= 1
Branch End
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Next would be to actually move the pictures to give them the highlighted effect.
Conditional Branch: menu == 0
Move picture 1: 150%, 150%
Tint picture 1: (pick a lighter colour)
*** NONE OF THESE SHOULD BE SET TO WAIT***
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Conditional Branch: menu == 1
Move picture 2: 150%, 150%
Tint picture 2: (pick a lighter colour)
Branch End
Etc. up to 3. Your pictures would've already been shown through a parallel process, so all we need to do is move them.