How often do you walk your dog? My puppy has not finished his course of vacinations yet, and I realise he won't want to walk far he's only very small, and will stay a small toy breed, I can't wait to start walking him but I'm not sure how many times I should take him out.
It's important not to over exercise a young dog as this can cause muscular skeletal problems in later life in severe cases. Keeping him entertained and active is more important than extended route marches.
Start slow - take him on a short walk around the block once a day to start with. You can gradually work up from there, just pay attention to see how quickly he gets tired.
Since it's a toy breed, walking will not be as much of a chore as with larger, more active dogs. Exercise is good, but as another user noted, be careful not to overdo it - especially early on.
A good guide for length of walk is five minutes for each month of age up to a year old. Eg 4 months, no more than 20 minutes at a time, although two or three times a day is ok, up to an hour at a year old. Free running is important too if you have somewhere safe. Do not overdo it or you will end up with a lean, leggy pup with no substance.