The Mayhem is on Eastnor Park. Not quite the malverns but close.
The Malverns can offer a mix of riding, however during the day time on weekends, theres sometimes so many walkers.
I think the best place to start is from Hollybush. If you go past the Mayhem entrance (eastnor park) coming from Ledbury, keep following the road for about 3 miles until you see a sign that says Hollybush, about 50 yards after this is a gravel car park on the left. Its free to park and starts you at a good height (even though you still have to climb). This is basically the start of the Malverns which is accessible easily.
From the car park, looking toward the hill infront of you, you can go two directions, up the tarmac/gravel road on the left, or, if you're feeling energetic, you can go right to the end of the car park and over the gate and head up onto hollybush hill itself. Both end up the in the same place.
From there follow the trail down and you'll end up at the back of Eastnor park, take a right through the woods and it'll take you up on the Malverns. Use the single track on the right which will take you to a single pedestrial gate (not the cattle gate) which you can go through and follow the path up onto the Malverns. From here, you can go where you like. You can pretty much see the whole of the malvern hills from this point.
One thing I would say is that there is no riding allowed on top of British Camp as its a protected monument. But to be fair, you're not going to know this since there are no signs. A great help. If you get caught by a warden I would claim its your first time there and you've come from Hollybush direction. They can only tell you to get off your bike.
As I said, the Malverns are full of walkers on the weekends so look out. Some dislike mountain bikers, but you are allowed to ride on the Malverns so just ignore them. If you see some no cycling signs then just redirect your route slightly.
Theres plenty of open trails and single track around the area and you can't really get lost. My advice is to avoid losing a lot of height, becuase you'll pay for it big time. 🙂
Have fun.