Okay… there's a lot to unpack there. I completely understand it may be overwhelming. Medium does have a habit of throwing everything at you all at once. I encourage you to seek out publication with their publishing bible posted on their pub menu bar.
I come from print background myself, with more than 25 years experience in graphic illustration and design — going all the way back to classic paste up and rubylith, moving on to creative software like QuarkXpress and the Adobe Suite, and on again to hand coded HTML web design. I also have experience as a proofreader, copy editor, and beta reader.
In addition, I've been blogging on multiple platforms since 2014. I can attest that, even though it has some problems, Medium is the best thing going for blogging. I wholly endorse it personally and encourage you to dip your toes with a $5 a month partner program membership.
As an offer of help, I invite you to join my writers forum on Facebook, "WE PAW Bloggers" group. I'm the owner/admin there. I'm also the owner/editor for the pub of the same name here. Here's a the FB link: https://www.facebook.com/groups/wepawblog
Here's another link to the pub here on Medium: https://medium.com/we-paw-bloggers
If you join the group on FB, you will be automatically added as a writer for the pub. I will help you any way I can to get a handle on things here. That's what the group and the pub are about — supporting and connecting with fellow writing creatives.
I also strenuously recommend following @Jason-P (Jason Provencio) here on Medium and join his Bouncin' and Behavin' publications. You simply cannot have a better person in your corner here on Medium than Jason. He's a man with answers and a generosity of heart to take you by the hand and walk you through the rough patches.