The text recommends worship during:
• the last 10 nights of Ramadan;
• both Eid nights;
• the first 10 nights of Dhu al-Hijjah;
• the night of mid-Sha'ban.
It separately dislikes turning the revival of these nights into an organized congregational gathering in the mosque. The recommendation is for worship itself, not for inventing a fixed communal ritual form.