Royal Mail pricing

New on here and still setting up my store. I am after some advise on royal mail settings as alot of my items are light weight and the postage charge the shop is automatically adding is way to high for a first class letter. and there is no specail delivery option. PLease can someone point me in the right direction as i am struggling and read loads on the board but couldnt find anything about altering the price. Thanks in advance Mark

Postage is calculated on Royal Mail small packet rates

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