Problems getting latest version

[RobertMason]

I am running Linux Ubuntu 64bit version 18.04.1

When I launch Sweet Home 3D via my desktop icon it launches version 5.7, but with a message that a newer version is available.

I have DL'd and unpacked SweetHome3D-6.0 from Sourceforge but I can't see an installer file or any way to get the existing package to update. sudo apt-get install pointed at the unpacked archive returns 0 to upgrade, 0 to newly install, 0 to remove and 15 not to upgrade.

Can you give me an idiot's guide as to how to do this, please?

[UbuntuBirdy]

From the "Download-Page":

Uncompress the downloaded file and run SweetHome3D application found in the uncompressed directory, possibly using this tip to launch it with a double click under Ubuntu. To install Sweet Home 3D, move the uncompressed directory in the one of your choice or read this article to create a launcher.