Open Delphys sims3pack Extractor (sims3pack Multi Installer) and in Step 1: click "browse", then navigate to the folder with your sims3pack file and click Ok.
In Step 2: click "browse", then navigate to the folder you want to extract the file to, and click Ok.
Tick the box “Rename Files on Save” and click Extract.
(Renaming files on save will give you the name of the file instead of some long number)
Go to the folder with your extracted files and either place in mods folder or convert the package file back to a sims3pack file and install.