Tim Harris says he's got a lot of work to do in a short amount of time after Hereford fell to back-to-back 3-0 defeats, having man sent off in both games.
The Bulls' Head of Football says his side can't keep giving goals away and they've been found out.
"You can't concede goals the way we concede goals," Harris told BBC H&W's Keith Hall.
"That's nine in three games and it's not acceptable really. There was times in the game where I thought we did quite well, and I think if Michael McGrath's header had gone in with the great save from the keeper at one-nil, it would've changed the game.
"These lads are finding what the National League North is all about because it's tough, we lack certainly the nous about this league. We've been found out and we've got to do a lot of work.
"It's going to be a tough job but it's nothing we didn't expect."
Mike McGrath was sent off in the second half after he picked up two yellow cards. The first for simulation after he dived in the box and the second for a reckless challenge.
Harris added: "You're down to ten men with a group of lads who are low on confidence and at the end of the day we just invite the game to them. They killed us off so fair play to Chester.
"I thought at one-nil we were in the game, I thought we were really in the game. But I talk about the nouse, the stupid free kicks we're giving away on the edge of the box, we're inviting trouble.
"We've had two or three opportunities in the last couple of games that I've seen to clear our lines, and we give the ball away and don't hook it on. Besides, Chester are a big, strong side like a lot of sides in this league, they don't give chances away, you've got to earn the right to score a goal.
"At the moment we're giving far too many opportunities to be punished and sides are taking advantage of that."
Harris was clear that change is needed in a short space of time.
"Where we currently sit at this moment in time, I've said to the players then, things have to change," said Harris.
"You can't keep putting in performances like that and expect to win football matches.
"If you're giving goals away like we're giving goals away then you're not going to stand a chance. If you get players sent off then that just makes it doubly difficult.
"We've got a lot of work to do in a short space of time."