I have my first plant ever growing. It's been about 3 days and it's around 2" long. I'm just wondering how long should I wait to put it into a bigger pot? Right now it's in a small dixie cup size cup. My other pot is WAYYYY bigger. and how should I go about doing it? Also, when do leaves start to form? Thanks so much.

I would put it into whatever pot you plan on using now. I put my clones right into 3 gallon pots on day 1 and leave them there until harvest.

When you transplant you should put your soil into the bottom of the new pot so that the plant will sit 3-4 inches below the surface. Cut the cup off of the plant and put it on top of the soil carefully covering the sides and top of the dirt ball with your new soil. Then give your plant a gentle watering and allow the new soil to settle.

Leaves should begin forming very soon. Maybe a week or less.

you can switch over to the bigger pot any time now

The sooner the better. Right after it sprouts if you can. Roots grow fast and will find the bottom sooner than one thinks.