How to open read notifications?
Assuming I'm understanding your question correctly, you want a "pinned" notification, meaning a notification that stays in the notification bar after you tap it and open the app in question.

If I am correct, you might want to look into apps that let you create your own notifications, like the app Custom Notification.

This could clutter your app drawer a little bit though; I know referencing Tasker without a specific task is poor form, but you might check into the Tasker subreddit, and tell them exactly what you are looking for. Someone might be able to recommend a profile that pins a notification to the status bar until you are done with it.