Each row in the Log View is one audit record: one thing that happened to one record in Dataverse, at one moment, by one user. The columns tell you which.

Figure 1. The Log View in flat mode, listing individual audit records with Changed Date, Event, Record, Entity, Entity Schema Name, Operation and Changed By.
The columns
Column What it tells you Changed Date When the operation happened. Event The kind of event, for example User Access via Web. Record The Dataverse record that was touched. Entity The display name of the table the record belongs to, for example User. Entity Schema Name The schema name of that same table, for examplesystemuser.
Operation
What was done: Create, Update, Delete or Access.
Changed By
The user who performed the operation.
Entity and Entity Schema Name are the same table
Entity is the friendly name a person recognises. Entity Schema Name is the name the system uses. They always describe the same table.
Both are shown because they are useful at different moments. Use Entity when you are reading. Use Entity Schema Name when you are comparing against something else in Dataverse, because that is the name that will match.
Operation values
Value Meaning Create A new record was created. Update An existing record was changed. Delete A record was deleted. Access A record was read.Access only appears if read auditing is switched on in Dataverse. If you expect read events and see none, that is where to look first.
Changed By is not always a person
Many audit records are generated by Dataverse itself or by connected services, so Changed By often shows SYSTEM or a named application user rather than a colleague. This is normal and it is not a sign of a problem.
Note
You can hide any column you do not need, and change the order they appear in. See Showing, Hiding and Pinning Columns.