If you are missing a part, the extraction will fail with an error message like "Next volume is required".

Download and install a tool like WinRAR or 7-Zip .

Right-click only on April.part1.rar and select "Extract Here" or "Extract to [Folder Name]" .

Are you of this archive, or are you seeing a specific error message when you try to open it? How to merge .part files using WinRar