How Old?

Dexter

Dexter loves to run outside , and he likes/is comfortable with his harness, but when trying to go on walks, he just sits and snifs stuff around him but is content to have me carry him and watch the surroundings change, lol. He is only ten weeks...is it too young for him to go for a walk just yet?

Leonberger

YES!
At ten weeks he's very likely not fully vaccinated, so no going on walks outside controlled environments. He's exposed to loads of stuff he's not fully immunized against, some of it potentially fatal.
So, please, until he's fully vaccinated only allow him out somewhere you know it's safe. Having said that, a good socialization is essential, so do carry him out to meet people and to be exposed to the normal noises of your surroundings, so he gets used to them. And if you have friends that you have fully immunized dogs that are well mannered around puppies, let him interact with them.

Kaddy

You might even be able to find a training place that offers puppy socialization classes. That what we did and it worked so well for us. We took her to play with small breed dogs that all had to provide proof of vaccination.

StaticNfuzz

Puppy training classes are pretty awesome for starters, you and Dexter can find some buddies that will help in the socialization department which is so critical at this age. Avoid dog parks and huge potty traffic areas for now.

Snf