Hi,
This was my first year too, but it turned out to be a big success ( I planted veggies & annuals under lights in Jan/Feb) My plants are HUGE!

Here is all I know....
You don't need to wash the trays if they are new. (at least that is what I read) That advice is only if they have been used, so that you kill any old plant germs out of them.

I used a soiless mix found a Lowes for $3 a bag. I know some swear by Promix & various brands, but the no-name variety I used turned out huge plants.

Any seed should germinate under your lights, but some take longer then others. I bought my seeds from heirloomseeds.com & Johnny's. Both did well.

Be ready to "pot up" I started in the 2" cells & went to plastic coffee cups before putting my seedlings out. (so you will only have room for a few plants- unless you set up a lot more lights or put your seedlings out very young)

Have fun & good luck!