Two weeks warm, then one week cold. It's a big beer, so you will probably want to age it to improve the flavor.
Now that your equipment is available, try making a lower-gravity beer. This will give you something to drink while the other one ages. Pick something in the 1.040 to 1.048 range.
I know you're eager to try it, but it's a disappointing feeling when the best beer of the batch is the last one you try. Sample, but think about storing a bigger beer longer.
If you're missing your gravities by a large amount when making extract beers, you probably need to pay closer attention to your water volume measurements. If you're doing a concentrated boil and adding more water at the end, make sure you have a good measurement of the final volume. Make sure it's thoroughly stirred and cooled before checking the gravity.
Welcome to the hobby.