Welcome to the community @saintnookie!
Unlike Squarespace, Webflow doesn’t act as a domain registrar (although I could definitely see this happening at some point) so you’ll need to transfer the domain over to a third party instead.
There are tons of domain registrars out there so it’s really up to you which company you want to go through—I personally use Hover for all of my domains but a simple Google search will lead you to find a bunch of other options (including Google themselves). Features between them all are fairly similar, with most offering first year discounts or specials if you transfer your domain from another registrar (like you’re doing), but long term pricing is pretty consistent from what I’ve found. If you’ve only got a single domain, it comes down to personal preference but while transferring is technically free, you’ll need to pay for an additional year on top of however much time you have left through Squarespace.
Transferring can be fairly simple with most platforms offering detailed instructions (especially when moving from a popular registrar like Squarespace) and I’ve found that whichever platform you go with should have no problem walking you through the steps if you get stuck or even making the changes for you. The basic idea is that you’ll need to unlock the domain, grab the authentication code, and then enter this code when signing up for the new registrar.
If you have a specific registrar in mind it may help in providing you with more detailed instructions, but the process is fairly painless even if it’s your first time
Edit: I’ve included the Webflow documentation below for you to check out which has a bunch of the details and even provides a list of registrars with links to their instructions on setting up the DNS—although as I mentioned, most registrars will be able to help you or even make these changes on your behalf: