How do I soften up the material on a new bench I just bought?

I'd call the co where you got it and see what they recommend. Do you know what kind of fabric it is? Does it have a fabric protestant on it? Did you order it or was it off the floor?

Is it a cushion cover that you can take off and wash? Sometimes they're starched to look nice on display at the store, and they just need a wash or two to soften up.

I bought at Tuesday morning it looks great but when you sit on it it makes you itchy

What is the fabric made out of? did you try it out before?- try spritzing lightly with https://www.amazon.com/KnitIQ-Rinse-Delicate-Liquid-Detergent/dp/B07KB53TVX/ref=sr_1_17?gclid=EAIaIQobChMIqIaG9NeH4wIVCv5kCh1Q6gnTEAMYAiAAEgIDxfD_BwE&hvadid=174223722363&hvdev=c&hvlocphy=9030040&hvnetw=g&hvpos=1o2&hvqmt=b&hvrand=479880126479320323&hvtargid=kwd-11631768072&hydadcr=21852_9445345&keywords=lanolin+for+wool&qid=1561570767&s=gateway&sr=8-17 mixed with water then apply an steam iron to loosen fibers;Pantene hair conditioner may work also don't use too much mixed with water or you will coat fibers too much--do it in stages until soft; rub the fabric briskly with some 100 % natural wool dryer balls (that the lanolin has not been prewashed out) the lanolin softens the fibers and rubbing raises the nap to add softness(as long as you are not allergic to lanolin); or you could do like they did in Medieval Ages-- Napping or Teaseling was done to raise the nap of the fabric enough to give it a soft, smooth finish. This was done by grooming the cloth with the head of a plant known as a teasel. A teasel was a member of the Dipsacus genus and had a dense, prickly flower, and it would be rubbed gently over the fabric. Of course, this could raise the nap so much that the cloth would be too fuzzy and had to be sheared again. The amount of shearing and teaseling necessary would depend on the quality and type of wool used and the result desired.Though metal and wood tools were tested for this step, they were considered potentially too damaging for fine cloth, so the teasel plant was used for this process throughout the Middle Ages. :) Since you like the design you could always remove top and recover it with something much softer/easier to have skin contact with that is si ilarly colored.