I'm still very new to chicken keeping myself, so take my advise with a grain of salt, but it seems like less is more sometimes.
Like black_cat, give them some space but still be present. I brought mine home as pullets who were already a couple of months old, so I was also worried they would never warm up to me.
The first few days I just ignored them. Went into their coop to clean, feed, and water but didn't touch or intact with them. Gave them time to just decompress and get into a routine. I would talk soft to them, just saying nothing in particular but let them get used to hearing me = nothing to be worried about. About 3 days after they arrived I started offering some treats (grasshoppers drove them nuts, but also mealworms). Within a couple of days they were running up to me for treats and I could feed their normal food from my hand. Now I'm mobbed anytime I enter their run, they officially think I'm the treat lady haha.
I'm sure they'll come around to you!