Here is a post about the differences between the 3 any% routes, and which one to run.

T2 (Tutorial 2) Route This route is the classic any% route that Runouw himself planned. You just finish Tutorial 1, beat Bowser 1, finish Tutorial 2, and finish Bowser Trap 3. A good run to see that uses this route is the current Tutorial 2 WR, you can find it on the leaderboard.

T2Skip (Tutorial 2 Skip) Route This is an alternate route that Runouw never planeed. Here, you finish Tutorial 1, then talk to Eddie so he gives you one star, then you go to Bowser Trap 1, kill yourself 4 times so your life counter hits 0, then when you're done fighting Bowser, you use the Key Cancel glitch that requires pause-buffering the key, then kill yourself, so you come back to the castle, and because you got the key, you unlock the FLUDDs and can play BT3 as you would in the T2 Route.

If you are a beginner and don't feel confident with the Key Cancel, you can just grab the key and kill yourself in the first hole in Tutorial 2. A good run to watch which uses this route is the current world record (7:47).

Hover FLUDD Only Route This route is clearly the hardest one, and it's the slower one (it used to be the WR route though). Here, you have to finish T1 and talk to Eddie so he gives you one star, then finish Secret of the Mushroom to get a second star, then grab the Hover FLUDD in the castle and enter BT3 with it, then you finish BT3 using only the Hover FLUDD, which is pretty hard to do fast. A good run to watch which uses this route is IHL's 8:45 run which can be found on the leaderboard.

Which route should I use ?

Here's the speed order between all the routes:

0) Tutorial 2 w/ Bird Strats -- TAS Route, only saves 2 seconds over the T2Skip Route, not viable for RTA because it's way too RNG heavy, don't use that lol

1) T2Skip w/ Key Cancel -- The fastest RTA-viable route, the current WR uses it. It's pretty reset-heavy because of the Key Cancel so I don't recommend it.

2) Tutorial 2 w/o Bird Strats (classic route) -- That route loses about 5-10 seconds over the T2Skip Route, I'd say ? It's cool for beginners, although it's by far less consistent than the T2Skip Route. Used to be the WR route.

3) T2Skip w/o Key Cancel -- Also a cool route for beginners. It's consistent, loses 15 seconds over the Key Cancel route, it's the route that contains the less resets in it. I recommend it for beginners that directly want to get a good time. Also used to be the WR route.

4) Hover Fludd Only Route -- Hardest route, slowest route, not worth the effort ;) It helps if you want to improve your general movement though! It's also pretty fun, but your any% PB shouldn't ever use that route. It also used to be the WR route though, like every other route in fact.

You should use the T2Skip w/o Key Cancel Route as a beginner, if you want to get a good time. Although it may be better to play Tutorial 2 and on average lose 5 seconds to improve the general movement instead of killing yourself 4 times during 40 seconds every run. Your choice.

If you get better, and have a PB that is around 9 minutes flat, then you can probably start going for the T2Skip w/ Key Cancel Route, if you get good at Key Cancel though. It saves 15 seconds but can kill 2/3 runs. Also your choice!