If using Sketch, copy your design to Figma for speedier access to the team in case of any mistakes or edits. Sharing a prototype is much easier from Figma.
Select the components and buttons that are clickable to direct the prototype flow.
After you finished prototyping, record a video walkthrough of the prototype, to give the rest of the team context on how the product looks and how the prototype works. The user researcher needs to understand where all your design decisions came from, how (and where) to click on the prototype and how the final product is supposed to work.
We don't share the prototype design with the client for sign off at this stage. We've found it's a step that fits better for enterprise, but not for early-stage companies.
If the client asks, feel free to share the link but caveat that you can't make changes or accept feedback until we have user testing results.
This should go without saying, but double and triple check the prototype is fully functional and accessible to everyone on the shared link.
Double-check the content against the original storyboard.