2 quick White tree frog questions

[KayJoh]

I know I have said this before but I really do appreciate the help. I actually hate coming onto forums because I don't want to be a pain in the butt to anyone. BUT... having said that your responses have raised a few more questions.
I have now decided that I would like to go down the planted route, they do look nice don't they! My first question is I know that you need your drainage layer but do you have to, from time to time, syphon the bottom right out to keep things nice and fresh?
Also am I right that you need a clean up crew and if so how do you ensure that they don't bring anything nasty in with them?
My plants will obviously be in before I get the frogs so is there anything I need to do for the plants until the frogs go in or will water be enough until the frogs arrive?
Lastly just seen something about cycling the tank. What does that mean? I know all about cycling a fancy goldfish tank but don't have a clue with this.
Can't tell you how much all your advice is helping already so again THANK YOU. X