where can i learn c# pathfinding?

im making a tower defence game, where can i learn how to code pathfinding, any tutorials? or can anyone start me off with a little code? thanks.

Pathfinding usually requires more than 'a little code', so it's unlikely you'll get any complete code samples here. However, there's at least a couple of third-party pathfinding libraries available that work with Unity that might meet your needs. (Search the forums for 'pathfinding library' and you should find them.)

Beyond that, pathfinding is a general topic that isn't tied to Unity or any specific programming language, so you can find info on it just about anywhere. Also, note that there are many different approaches to pathfinding, and which will work best will depend on the context. So, if you need more specific advice, it would help if you could provide more information about the setting. (For example, what's the environment like? Is it grid-based? What sort of obstacles are there? And so on.)

Your path starts here.

Here is some basic code you should start of with.
public class pathfinding{

good luck.

Look up A* Pathfinding, its free and a good simple library to use!