when you enter the twilight river, you'll be trying to find olimar...
theres 3 bridge piles you'll need to collect before you can get to the pink pikmin. sorry i meant flying pikmin
you'll need to use yellow pikmin for an eletric gate and a lightbulb, the latter of which will be used to activate bloominous flowers in a cave, and you'll need to bring rock pikmin, due to a pile of bridge pieces being inside of a crystal
going through the only path with dry land, you will find a stream with lily pads! you can hop on these to transport your entire squad to the other side of the body of water :)
on the other side of the stream, you will find an electric gate, and a crystal with bridge pieces in it. behind the gate will be a wollywog, and a pile of bridge pieces.
further down the exposed path will be a puffy blowhog, a bomb rock repository, and a cave. the inside of the cave has no enemies within it, and houses a lightbulb that requires 20 yellow pikmin to activate. once activated, bloominous flowers will bloom, opening up the way to the final pile of bridge pieces
once over the fallen tree, which acts as a one way bridge, there is a UGH I FORGOT THE NAME. FLYING POKER, and a reinforced wall. pikmin are able to go through a path next to the wall, but will have to go back to the pile that they were assigned the long way if the wall is not destroyed
also its generally not good practice to leave enemies along a trail where pikmin are carrying things. so you know.
good golly! i love fragments strewn across incredibly large areas!