From the Super Mario Wiki
Tree Fortress is an official course in Course World in Super Mario Maker 2. It is the eleventh level published by NintendoUS, uploaded on October 2, 2019. It is set in the forest theme and in the Super Mario Bros. style.
The level starts out with six coins leading to a yellow pipe taking Mario to an underwater forest section of the level. Here, there is a Key Door and thirteen more coins shaped like a diamond. At the top of the water are two more coins and a Trampoline Mario can bounce to reach another trampoline, which he must bounce on to reach five coins. Next is a Swinging Claw which takes him up to Bumpers with three coins. There is then another trampoline which he must bounce on to reach five coins on a Seesaw, with five more coins above it. Mario must carefully bounce on a trampoline moving on a Track to get up to four coins, with a vine leading him to a section with Lava Lifts and vines in Music Blocks. More coins can be found here. At the very top is a key. Below it is a ? Block containing a 1-Up Mushroom. At this point, Mario should have 57 coins. He can then fall to the bottom and enter the Key Door, which takes him to a Checkpoint Flag.
To the right is a ? Block containing another 1-Up Mushroom. Mario must fall through a set of Grinders and Bumpers, with coins along the way and a 10-Coin at the end. There are then two groups of coins near a yellow pipe leading back to the main area. Here, there is a vine which takes Mario up to the final coin. There are also Twisters nearby on Flimsy Lifts which can lift Mario up to the Goal Pole.
"Forest adventure awaits! Can you collect all 100 coins?"