It is hard to know when to take a puppy out to use the bathroom, as they don't have a lot of control over their bladder when they are very young. At one point, my two-month old puppy was going to the bathroom about every half hour, so we let him out frequently when we were home.
From The Kennel Club:
Puppies have very poor bladder control, and need to urinate at least every hour or two. They can urinate spontaneously when they get excited, so take your puppy out frequently if it has been active, playing or exploring.
It is really important that you are taking out the puppy from its crate as soon as you get home, and as soon as you wake up in the morning, as you are doing now.
Eventually as they get older a pattern will develop, and they will also learn to warn you when they do need to go outside (from my personal experience - whining, automatically going to the door, or a combination of the two) to go to the bathroom.
There is a good Wiki-How article on how to house train your dog, as well as how to properly deal with it when they have accidents inside.