How to get all messages post by person in team channels using power apps in teams

I have teams group in which there are multiple teams channel. I want to get all the post messages by any user and from those messages only want messages which contains "Open" as a string in first line of the message in combobox/Gallery to select by user.

I have tried using combobox MicrosoftTeams.GetMessagesFromChannel() function it was showing some id. I also tried with Gallery with some function and inside gallery I select layout as title and selected only body of the message. It was showing html text with message so I used HTMLText but now it is messed up all messages. I enable scrollbar but still it is not scrolling. I preferred Combobox to shows messages of user with string "Open". Can Anyone suggest me how Can I get messages properly.

1.First, you need to gather all the messages from the Teams channel. You can use the MicrosoftTeams.GetMessagesFromChannel() function to get the messages.

2.Then use a formula to filter the messages that contain "Open" in the first line. You can use the StartsWith function to check if the message starts with "Open".

3.You can use the "Filter array" action to filter messages where the sender's email or name matches the specific member (selected from combo box).