I presume you have an accountant. Talk to him/her. Preliminary tax is based on either the liability for the current year (which you don't know) or the liability for the previous year (is this your first year?).
If it is your first year, I would make a rough estimate of what you expect the tax to be and pay that. Obviously if it is too much, you will get any excess back.
Your ARD is issued by the Companies Office and is generally not linked to corporation tax, unless you have changed the ARD.