So we've determined that there wasn't a space battle above Geonosis and that the clones landed in Republic capital ships. We know that Yoda went and gathered the clones from Kamino. But where did they get all of the ships/supplies to transport and equip an entire army? We know they'd been working on a motion in the Senate, but I doubt they could've gotten funding to build all of those ships let alone had time to do so.
Millions of clones basically do you no good if you can't transport them somewhere.
This is a quote from the novelization of the Star Wars Episode II: Attack of the Clones:
"Master Sifo-Dyas requested the most powerful army in the galaxy. We have worked with only the best shipbuilders to fulfill that request." ―Lama Su
The novel is considered canon, and Wikipedia has this blurb.
The Star Wars Episode II: Attack of the Clones novelization was written by R. A. Salvatore and published on 23 April 2002 by Del Rey. It is based on the script of the film of the same name. It includes much expansion of scenes and also many scenes which were cut from the movie. Some of them are original to the book.
In the Star Wars novel Tarkin (also canon), there is this exchange between Tarkin and Dooku just before the attack on Geonosis.
Tarkin tried to decipher the count's inference. "One might almost conclude that you're positing an advantage to going to war. But how would that work? The volunteer security forces of the Confederate worlds against--what, Judicials and ten thousand of your former Jedi brethern?"
Dooku adopted an arrogant expression. "Don't be too surprised, Governor, if the Report has access to secret forces."
Between these two quotes, I think it safe to infer that in addition to building troops, they were also building the hardware necessary to make them a functioning army.