Meilin mountain is more of a hill than a mountain, however it is a nice couple of hours in the fresh air. at maximum it’ll take you 3 hours to finish probably less and that’s what makes it great, it can be done in a morning or afternoon.
There are stairs here, but to the side of them there is a dirt path for most it. Even so the stairs are not particular tough and it is suitable for beginner. there are numerous rest stops along the way and a pagoda at the top to rest too.
You start near Qiaoxiang metro on line 2, exit C. Cross the road to Vanguard the walk up the road and cross the bridge over the highway. Follow the route up and up.
Going down you will end at Meilin reservoir, just keep going down.
complete list of hiking in SZ here Hiking in Shenzhen