Hi Profmar,
Glad to hear you've got the book a professional cover and it's been edited.
Instafreebie if memory serves will allow you to disseminate your book for free to other but I believe you need a subscription to gain access to the sign ups. If you've an author website you could use a lead page or an email signup field on the home page to capture user emails and then send them to a follow-up email with the ebook link.
By already having a social media presence means you can start leveraging your existing followers for the creation of the launch team.
Here is some information on what launch teams are: https://onestopfiction.com/community/blog-for-authors/what-are-launch-teams-why-you-need-one
And a Blueprint on how to go about using them to successfully launch your new book: https://onestopfiction.com/community/blog-for-authors/2-month-blueprint-for-self-publishing-and-using-launch-teams
Additionally feel free to join our FB group for more help on marketing. https://www.facebook.com/groups/OneStopFictionBookMarketing/
-Kent