This task was easy to complete. First I opened the ‘Find in Message’ window using the following path:
Evolution → Message Name → 1st <no name> → 1st <no name> → 1st <no name> → 1st <no name> → 1st <no name> → Edit → Find in Message... → [Take Action]
Then, I used the ‘Find in Message’ window enter a word:
Evolution → Find in Message → 1st <no name> → 1st <no name> → 1st <no name> → [Text]
Finally, I found the word several times in the message using this path:
Evolution → Find in Message → 1st <no name> → 2nd <no name> → Find → [Take Action]