The first coin is not too far from the start of the level. Bounce off a Koopa or use ... find the Wonder Flower hiding in clouds. Once in the Wonder Flower sequence, you'll need to control Mario ...

Upshroom Downshroom is the first Course in World 5 - The Fungi Mines in Super Mario Bros. Wonder ... you'll learn where to find all the Wonder Seeds and Flower Coins in the Upshroom Downshroom ...