The video preview spoiler on itv.com for Wednesday 19th shows Emma finding Ross' mobile phone in one of Ross' bedroom storage containers. Finn then tells her it's Ross' old pay-as-you-go phone with Donna's old stuff on it. So Ross presumably had a new phone with him when Pete dumped Ross in the woods. I guess that the phone would show Ross on a map using GPS where he was and then he was either able to walk out of the woods by himself or to phone a friend to come and collect him from the woods and get treatment for his injuries in someone's home/hospital somewhere. Alternatively, maybe a dog-walker found Ross (dog smelled Ross and brought the dog-walker to the body) and took him away by helping him walk to his car nearby.
Source: http://www.itv.com/emmerdale/preview...wed-19-aug-7pm