I am a VAT registered startup company and end of march is my first VAT payment

am about to re-enter my sales and purchases for the 2nd time after making lots of mistakes and things got messy! I have not had many sales / purchases so this wont take me that long (I hope) but need some very quick and simple advice for my VAT entries.
I have made some puchases, some I have paid VAT on and some I dont pay VAT because I supplied them with my VAT number.
I use Sage Line 50 (v12).
I create a Purchase Order and I enter all the details etc for the purchase.
For all products from "Supplier A" I dont pay VAT so do I enter T0 as the tax code? Is this the correct code or do I assign another tax code. This supplier is also based in Europe? Does this make a difference?
For "Supplier B" who is UK based they charge me VAT so I use T1 at 17.5% for all purchases.
All my sales invoices include VAT at 17.5%.
I assume that when I use the VAT wizard the VAT is only calculated on sales and purchases that are under tax code T1.
Can you confirm if this is the correct way of going about this.
Thank you in advanced.