Download Diamond link: http://www.latticesemi.com/Products/DesignSoftwareAndIP/FPGAandLDS/LatticeDiamond#windows
Then there is the license. The method to obtain the license is also very simple. Click to obtain the license and fill in the mac address on your computer.
Then go to the mail to download it.
There are many ways to set up a license on the Internet, but some are feasible and some are not. Here I write the method I use, which is simple and rude.
Directly on the picture above, this computer clicks properties, selects advanced system settings, selects environment variables, create new, and fills in the variable LM_LICENSE_FILE, and the value fills in the path of the license you downloaded.
This completes the installation.