How can I use lines 2 tubes plugin?

Hi guys. I have a very complicated mesh model and I wanted to make all the lines into tubes. However, I have 2019 Sketchup and the most updated lines 2 tubes plugin can I find is 2014 version and it doesn’t seem to work in 2019. I downloaded 2014 of Sketchup Make but I couldn’t find “extension manager” for me to install the plugin. Is there any way I could install it or is there any similar free plugin that I could use? Any helps is much appreciated, Thanks!

For older versions of SketchUp, look at Window > Preferences > Extensions
and for SketchUp 2019, to use Lines 2 Tube, use the JHS Powerbar v2019 plugin.

Thank you for your help!

There’s also a PipeAlongPath plugin which does the same sort of thing.