Use The Unarchiver or Unzip One to open the first part of the sequence.

Use an app like ZArchiver to navigate to the files and extract the .001 part.

Download and install 7-Zip. Right-click the .001 file, select 7-Zip , and then click Extract Here or Extract to [folder name] .

You may be able to right-click the first file ( .001 ) and select Extract All directly in File Explorer.

You can use 7-Zip on any computer, including a computer in a commercial organization. You don't need to register or pay for 7-Zip. How To Open .7z Files on Android

Do you have the of this archive (specifically the .001 file) saved in the same folder?