Building an e-mail list slowly and steadily through scraping social media 
what app / software / website do you recommend I should use to e-mail them? I have never done e-mail marketing in the past, literally 0 experience. They are under a specific niche and I’d like to promote a specific product.
cold emailing might be a start for you
check this thread:
https://mpsocial.com/t/the-1-mistake-people-make-when-sending-cold-emails/110748
You can use Jarvee to send bulk Emails. Just add your Email account then add Emails you want to contact and then use Campaign to send them Emails.