Why did you download Mojave from a torrent, there is no need Mojave is still available from Apple.
Open your Safari browser and click on this link,
How to get old versions of macOS – Apple Support
Although it is possible to upgrade directly from Mac OS X Yosemite to macOS Mojave
I would recommend you upgrade to macOS High Sierra first as this will prepare your
mac for the new APFS file system.
Go to Check Compatibility to see if your mac qualifies for the OS you want to install.
Then go to the Download section and then download the OS you want.
You will be redirected to the App Store download page for the OS you want
it should say Get or Download.
This will download the Install macOS *******.app to your Applications folder.
If you want to create a bootable USB flash drive follow the instructions here,
How to create a bootable installer for macOS – Apple Support (UK)
Before upgrading make a full back up of your Mac.
Check that third party apps you use have updates available for the new OS.
https://roaringapps.com
Check that your printers/ scanners etc have updated drivers and software available for the new OS.
Connect your mac to your router via cable rather than rely on WiFi.
Do not use your mac while it is downloading
and do not use any other devices that share the same internet connection.
If the App Store says ‘Open’ then it is detecting a previous download of the install app
go to the Applications folder locate Install macOS ******.app.
Move it to the Trash, empty the Trash.
Restart, click on the link again, the App Store should say ‘Get' or 'Download'.
