The first few attempts at anything new with our students takes more time then we anticipated. I always tell my student teachers to plan for more then they think they can get done in a period and expect that you'll only get to half but it's better to have more ready then to not be ready.
As for your routine, good job with the color coding. The first few times will take twice as long as you'd like since you will be walking them through it.
Once you notice that a few students are starting to get it. Make it into a game/challenge. Set a timer, for each of those students or table groups, that is ready before the timer, they get a point toward a reward (popcorn party, no homework on Monday, an extra pick from the daily prize box, a pick from the big prize box, etc) you determine how many points to till the reward is given, depending on your students level (mild = 4 points), (moderate = 2 to three points) or if individual those with X number of points at the end of the week get the reward. Once the majority of the students are within your time, you can either make the time shorter, only set the timer a few times a day/week, eliminate the challenge, etc. It all depends on how it's working for you. For those students who never made it to the challenge, those are the ones that need it structured up more or differently. Don't forget to work with them as not every structure/process works for everyone.
I have one student who has all his notebooks and work in his desk nothing is located around the room, like the other students, because it takes him 10 minutes to get his items and get back to his seat. So we made the desk next to his empty so that his items can be in there also.
My 1st day is the 2nd also, good luck. Let me know if this needs further explanation or any other guidance.