You might be better off just going down the very simple route, and just create new views in your Events table — each one of them filtered by a single topic. Then you can leave everything setup just like how it is setup now, and you don’t need to worry about linking tables (and the limitations that go along with linking tables, as I explain below).
But if you’d like to really set this up with the ideal database design (and it’s your choice if you want to go down this road), you’ll want to setup this join/junction table. That’s actually why I suggested that you simply start by doing your data entry in your new join table, simply so you can visually see what’s happening behind-the-scenes, and then you can take a look afterwards to see how the Events tables & the Topics tables look after you’ve manually added some records into your new join table. (In your Events & Topics tables, you’ll need to “unhide” any new fields that Airtable has automatically added to those tables.)
You don’t need to keep doing data entry in your join table, but you can just start off that way to see how Airtable works in this fashion.
From the Events table, it will be almost identical to what you have now, except that it will be very different when you’re adding new topics to an event. Let’s say that you have one “Events” record with 8 topics associated with it. In your Events table, you will end up seeing one linked record field with 8 topics attached to it, but all of those 8 linked records will be living in your join table instead of your Topics table.
So you’ll actually be CREATING new records in the join table whenever you need to add a new topic to an event. But you can do all of this from the Events table in the new “linked record” field that links to your join table.
Any new linked records that you create will automatically have the “Event” linked to them (because you’re creating them from the Events table), but you’ll need to manually add one new record for each linked topic.
Airtable’s interface for this will be a pop-up window that appears, so it will be a very different interface than what you’re currently used to. And when this pop-up window comes up, you might be initially overwhelmed because it will show you all the pre-existing records in the Join Table. You’ll want to ignore all of these pre-existing records and just click on the “Add New Record” button at the bottom.
(Even better, you can limit your linked record field to ONLY showing you records from a particular view in your Join Table, so you can create a view that shows you no records at all — then you won’t be overwhelmed because you’ll just be looking at a blank window, so you’ll instinctively know to click on the “Add New Record” button at the bottom.)
Oh, and one very important thing that I forgot to mention previously: One of Airtable’s gigantic limitations is that Airtable will ONLY display your “Primary Field” in a linked record field after you link records, so in your Events table, you will only see the values from the join table’s Primary Field in your linked record field. In my personal opinion, this is one of Airtable’s biggest limitations & weaknesses. What this means is that in your Events table, you’ll ONLY see the Primary Field value from your Join Table in your linked record field, so it’s going to look a bit weird. Since you always want your Primary Fields to be unique values, in your join table you’ll probably want to use a formula for your primary field that is a concatenation of your topic & your event. So this will look pretty strange in your Events table’s linked record field, because you’re not just going to see a list of categories like you see now. This is why I think that this is a huge limitation of Airtable. However, you can add “lookup fields” to your Events table to display the values that you want to see from your join table in an array (i.e. separated by commas) — so that will be a nicer way of looking at your topics. They will be a simple list of topics that is separated by commas.
(And — another limitation of Airtable which isn’t a limitation in other fully-relational database systems: If you actually remove a topic from an event later, you’ll end up with some “orphan” records in your join table. So, from time to time, you’ll want to filter your join table for any orphaned records and delete them from the join table. You can create another view for this as well.)
If you feel like going down this road, it might be best to just dive into creating this join table without trying to fully visualize it too much ahead of time, because it’s somewhat complex to setup, and if you’ve never done it before, it probably won’t make much sense until you actually start building it & seeing it in action. You will be dealing with 2 or 3 Airtable limitations (as I mentioned above), so you’ll have to see if you’re okay working within these limitations that Airtable presents to you.
But the cool thing is that you’ll be able to do all of your grouping/sorting of topics & events in this join table, just like how you originally envisioned!
Also, if your company has a budget for this and you’d like to hire a professional Airtable developer to help you set this up, please feel free to send me a private message as well!