SignRequest Plugin Help

Could someone help me understand better how I am supposed to build this feature out? So I am building a SaaS application for real estate agents and I need to allow users to request signatures, upload PDFs and add text boxes, dates, initials, checkboxs and signatures.

I am currently trying to use the SignRequest Plugin and I am lost of how to get it working. I am trying to get a simple request working, in order to getting understand the plugin. I am a newbie with code and no-code. So I am for sure missing something obvious and simple.

Thank you ahead for the help.