Aligning Index Navigation : NEXT (inline) to Justify left and adding PREVIOUS button

Site URL: https://gregoryherman.com/spiderman-far-from-home-main-on-end-titles

Looking for some help with code on a few custom tweaks that my LANGE template (york)  cannot do.

1. Left Justify the "NEXT" to match the other left justified text...

2. Add a "PREVIOUS" Button so you can go back and forth...

I realize the index navigation for NEXT falls inline with where the entire site is justified...

Mine is set to "center," which Is why the "NEXT" is defaulting to center..  I want to keep center, but move the "NEXT"

I tracked this down and tried it, but nothing happened..

Am I getting close?

.index-next-link {
    align-text: left;
}

Locked in on aligning the NEXT button... GOOD ON THAT...Thanks..

Now figuring out how to add the "previous" button in ... Slightly more complicated.

I didn't realize  the other thread wasn't yours. This is what I worked up for your page.