[Paul Bennett]

Several things, Luke, not to dispair.
1. Initially one checks for spark at the spark ignition coil center wire, not at the spark plugs.
2. Your battery should be permanently connected to the ammeter (step 1). Verify this with a test light. If you don't have a test light, stop everything and get one (a necessity about the price of a hamburger)... become comfortable with it by connecting its long wire to ground, connect the battery and poke hither and yon and observe. Toss the voltmeter to your grandkids. For now anyway.
3. (step 2) Verify that the other side of the ammeter is be permanently connected to the ignition switch through the breaker assembly. Verify this using the test light.
4. When you turn on the key, test test light should indicate voltage at the ignition coil side wire.
5. Factoid correction to post 3 item 2 ... a '53 starter button has voltage permanently running to it. This voltage is applied to the starter solenoid when you press the center with your thumb. Note the center push part of YOUR start button should be black plastic. Pressing the button on a '53 Merc applies voltage (not ground) to the small connection of your starter solenoid. Earlier cars do apply ground and their push element is chrome (but not yours). Ask me how I know. No don't, I'm troubleshooting an intermittent pb on my '50 Merc (with a chrome button) as we speak.

Complete your assignment and report back for your next round of 'Let's get this thing on the road' once and forever. Carry on soldier.

Incidentally, you should be connecting and disconnecting power at the negative battery post not hooking wires here and there. Until you are running, disconnect the battery while not troubleshooting. Save the electrons.