The first thing you need to do is to is to re-brand those plr. Change the cover, update the content because some stuff could be outdated and put your name on it.
Also add your affiliate links within the content, to maximize revenue. Fix any grammar or spelling errors and change the font to a more appealing one. And make the content easy to read because most plr have huge blocks of content so add some headers and make paragraphs short. Simply make it easy on the eye.
Once the re-branding is done then you'll need to have an autoresponder account. You can use any autoresponder service you want, but for beginners I recommend getresponse or aweber.
Then you'll need to create a squeeze page, if you're using getresponse then you can simply use their free squeeze pages to capture leads. There's a lot of great tools out there that can make this process a lot easier. Things like leadpages, optimizepress, clickfunnels, thrive content builder, profits theme etc.
Use your squeeze page to collect people's info like name and email address then use your autoresponder to email them the book. Those are the steps you need.
I don't know if you need some more steps about what you do after sending them the book, but I'll just stop there. Hope that answers your question.