Help with ammeter reading
Connecting an ammeter directoy across the terminals of a battery reads a current.

It sure does - for an instant before something is destroyed.
Presumably you thought this would be a good way of figuring out what current the battery could supply. It's not, because you have connected the + and - terminals together so you have 0 V out of the battery so, while very high current is flowing, the voltage is zero so you can't power anything.
What you have done can be very dangerous with the wrong type of battery. The current is only limited by the internal resistance of the battery.
Instead, connect the battery to a known load that is within the discharge rating of the battery and the rated current of the ammeter. Measure the current and measure the voltage that the battery supplies while varying the load. With this information you can characterise the battery.
If you are fortunate the internal fuse will have blown and your meter won't be destroyed. Please read the manual for the meter and find some good tutorials on multimeter use and follow correct safety procedures.

From the comments:

If there is zero voltage how can there be a current?




simulate this circuit &ndash; Schematic created using CircuitLab
Figure 1. (a) High current flows when a battery is short-circuited with an ammeter. (b) A safer test circuit.
In (a), your measurement circuit, there is no voltage at the battery terminals because you have shorted them but there is voltage the other side of the internal battery resistance. The current will be determined by the sum of the RINT + RAM1.
In (b) we use Rtest to limit the current to a safe value. By measuring the open-circuit voltage and the loaded voltage we can calculate the internal resistance.

Also my voltmeter when I do this reads a voltage across the terminals of the battery? I am aware of the concept of voltage/pd but am unaware how it measures these values. why would doing this read zero volts on the volt meter?

A schematic is much better than words. Add one into your question, a link to the datasheet of the battery and the multimeter and show how you are connecting everything up.

Also i a amp meter has HIGH resistance why can this short a battery as no current should flow?

You mis-learned something here. Voltmeters have very high resistance so they don't draw much current from the circuit being measured. Current meters have very low resistance otherwise they would restrict the current to the load.