When using Thunderbird (versions 102 and higher) you do not need any special addons. Thunderbird core can synchronize using the "vcard" and "vcal" standards.
Click the "Address Book" icon in the top of your window
Enter your username that you use to login via https://share.mayfirst.org/ (note, the user must be configured with Nextcloud access in the control panel).
For location, enter: https://share.mayfirst.org/.
Choose the contacts you would like to synchronize.
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