Hi @Erik B.17, thanks for messaging the Community!
Currently, you can only connect 3 devices to a Dropbox Basic plan. This means using the Dropbox desktop application or mobile app when signing in.
However, you're still able to login manually via the site, as this isn't considered a 'device' as such, so you can always do so to access your files, and upload, delete or edit them
If you have any further queries, feel free to message back.