Moses Christensen told officers his intention was to "go out and kill or be killed" as he searched south Shropshire's Brown Clee Hill before the killing of Richard Hall on August 13 last year.
The third day of Christensen's trial at Stafford Crown Court was read extracts from interviews carried out with the 22-year-old at Telford's Malinsgate police station on August 17.
In the first of two interviews, the court heard, Christensen told officers: "I had planned to kill people.
"It was sort of a gradual, long process for me. It was planned, it was calculated to a large extent. I think that's a very important point."
The case so far:
Informing police that he had been living rough for around three days when he killed Mr Hall, Christensen added that his plan was "nothing personal" and that he had "wanted to do it silently" without any witnesses.
Jurors heard that he also told officers: "I was roaming around, intending to find targets... some small groups who I thought I could overpower."
Asked by a detective about an elderly couple he had not attacked, Christensen responded: "I didn't feel comfortable. I could see people on the hillside in the distance so I planned for further targets. That is what I was doing."
Addressing the fatal attack on Mr Hall, who lived in Perton in South Staffordshire, Christensen told police that foggy conditions had provided a "good opportunity", with many of his "criteria" in place.
Christensen, of Corser Street, Stourbridge, West Midlands, is alleged to have been soaking wet when he was arrested by police in the Burwarton area on the evening of August 13.
According to his account to police, Christensen had submerged himself in a pond after the killing, where he hid from what he assumed to be a police helicopter looking for him.
Giving evidence via video-link on Thursday, Home Office-approved pathologist Dr Brett Lockyer said Mr Hall had suffered a total of 26 injuries, including a "horrific" wound to his hand and another which had penetrated his skull.
Mr Hall, who was killed by wounds to his neck and chest, would have died in "seconds to minutes" due to the severity of his injuries, Dr Lockyer told the court.
Jurors have been told they must decide whether the unlawful killing of Mr Hall was murder or manslaughter on the grounds of diminished responsibility.
The trial continues.