The "Message" section of a rule holds the text that goes out with each share. The link to the post is added at the end automatically. Line breaks become spaces.
Placeholders
Placeholders are filled in for each post. The "Insert" buttons add the common ones, and you can type any of them:
{{ title }}: the post title.{{ excerpt }}: the excerpt. The Insert button adds{{ excerpt | truncate:120 }}, which cuts it to 120 characters.{{ content }}: the post content as plain text.{{ author }}: the author's name.{{ terms:category }}: the categories, separated by commas. This works with any taxonomy, for example{{ terms:post_tag }}for tags.{{ published_at }}: the publish date.{{ canonical_url }}: the link to the post. You do not need it, because the link is added anyway.{{ meta:name }}: a custom field. The field must be listed under "Advanced", "Custom fields used in this rule".
Add | truncate:N inside any placeholder to cut it to N characters, for example {{ title | truncate:60 }}.
The character count
Under the message, a live preview shows the message for one of your channels with a count such as "120 of 280 characters, including the link." PressQueue keeps each message within 280 characters on every network, and the link counts. For Mastodon, PressQueue uses the server's own limit when it is lower.
If the text is too long for a network, the preview says how many characters too long. Shorten the message, or cut the excerpt with truncate.
A different message per network
Under the main message, "Write a different message for ..." offers a field for each network your channels use. Fill one in to use another text on that network. Leave it empty to use the main message. The Rules page then shows "(own message for X)" next to the rule.
The preview
The preview uses one of your recent posts and says "Using" with its title. You can switch the post and pick the channel under "Preview for channel". The test after saving shows the full text for each channel.
Message templates
Messages you use often can be saved as message templates and copied into new rules.
Changing the message for one post
Open "Customize for this post" in the editor and write a message in "Message". Leave it empty to use the rule's message. See Sharing settings for one post.