Follow these steps to subscribe to a mailing list as a regular subscriber (non-admin).
Each mailing list has its own information page you can open directly.
If you do not know the listinfo page url but you know the list address you can derive the url:
For a list address such as: example@lists.mayfirst.org replace the @ symbol with a period (.) and append it to the base url https://a.lists.mayfirst.org/mailman3/postorius/lists/
Example info url:
https://a.lists.mayfirst.org/mailman3/postorius/lists/example.lists.mayfirst.org/
Open the resulting URL in your browser.
Depending on the list configuration, your subscription may become active immediately or require admin approval.
To subscribe to a list such as example@lists.mayfirst.org, send an email to the corresponding request address by adding -request to the list name:
example-request@lists.mayfirst.org
In the email body (or subject), include only the word:
join
Do not include any other text.
If the list allows new subscriptions, you will receive a confirmation email. Reply to that message to complete your subscription.
To learn more about subscription policies and mailing list types, see About mailing lists at May First.