Here's something i posted a way long time ago...
one thing is that you have to know your front load. some will allow you to open the door after the cycle starts and some won't. mine lets me until it gets to the spin cycles after that i have to pretty much wait it out.
i put mine in a pillow protector too with as many old jeans as i can find and even a couple of pairs of old tennies. i have never been able to felt as fully as others but that could be because i am not patient. [eta: I was able to fully felt Malabrigo successfully without having to go through a lot of cycles] you might need to add some hot water through the process and run it through more than once. i would avoid having it spin out if possible just keep resetting it back to the beginning. also don't forget to shock it with cold water in the process as well.
it may take several rounds through the machine to get it as felted as you would like but it can be done!
big thing, before you start, is that i would test the machine to see if it will let you open it once it is started. Some do, some don't, and like mine, some will for a while but once you get to the spin you have to let it finish.