Place Slope Pipe

Good afternoon.
I am trying to place a slope arrow (which is just a generic annotation as I’ve read you can place the out of the box slope arrows using dynamo) onto the center line of a pipe. Could you help to me how can do.
Thanks

Adding a screenshot of what you tried could help to get the appropriate answer. Please use Dropbox or similar if needed…

Thank you .

you can see in the figure