First set a budget. It's great that you have this much time to save (average wedding is about $35,000 for 100 people). Then start creating a tentative guest list and visiting venues. You don't have a wedding date until you've secured a venue. Everything else after that can wait a while (within a year of wedding).
We arent getting married until September 2023 and I already feel overwhelmed with planning lol.
This website has really helped with the timeline.
I am also extremely extra when it comes to planning any event. I started off with making a powerpoint of all of my wishes/ideas. Dresses I liked, my color scheme, decor inspo, guests list, bridesmaids/groomsmen lists, dresses I liked for my bridesmaids, outfits I liked for the groomsmen, picking out who I wanted as the flower girl/boy, the ring bearer, and officiant, food ideas.
I then made an excel sheet of everything I knew I needed and started planning out a budget. I have also already started contacting a bunch of different vendors so I can get multiple different pricing and be able to narrow down my choices.