Curing fresh ham with limited ingredients
General information on brining and smoking a ham can be found in many online sources.  Here's a good one with illustrations.  I would draw particular attention to the injection step.  If you don't inject a large piece of meat like a whole ham, it will not cure evenly (or will take a ridiculously long amount of time to cure).  If the ham is particularly large and you don't have a syringe or brine pump, the other option can sometimes be to cut up the ham into smaller pieces and brine them together to allow greater penetration of the cure.

Since you don't have the Prague Powder, you should make the brine using only water and Morton's Tender Quick.  You substitute that for the salt and Prague Powder, following the directions on the package.  I've never used Morton's Tender Quick for brining personally, but online sources seem to imply that the package indicates 1 cup per 4 cups of water.  That seems like it would make a rather strong brine, but when curing meat, you should follow the cure manufacturer's recommendations to ensure safe preservation.  (If the meat is too salty after curing, you can soak the ham in fresh water for a short time to release some of the salt.)

UPDATE: Here's a link to what appears to be the text of Morton's own detailed pamphlet on home curing.  Morton's own website mentions to refer to this when curing large pieces of meat like ham.  Proportions for brine are given on a later page.  Here they recommend for injection brine strength:


  2 lbs. of Tender-Quick per gallon of water for meat that is to be
  kept for only 3 to 6 months.


And they recommend injection:


  The amount of Tender-Quick pumping pickle to use is 1 to 1 1/2 oz. of
  pickle per pound of meat.


While this describes the injection step, the rest of the information in this book describe methods for dry curing or wet curing with Morton's sugar cure mixtures, rather than Tender Quick.  (However, I will note that early on the book clearly states that Tender Quick can be used instead for all curing processes; it just doesn't seem to give proportions.)

I should also note this Morton's method is designed for true long-term meat preservation, rather than a quick curing method to make something that will be ready for Christmas.  (They say that hams should be brined for 3 days per pound, which if you have a 20 lb. ham will take 60 days.)  Since you're presumably just curing the ham for flavor, not for long-term preservation, a couple weeks using their suggested method followed by smoking should still give you a good product in time for Christmas.