Sorry, I can't really help with that. I've always used schematic capture for my CPLD designs, and am limited to hacking existing code for anything larger. I just learn it as I go along (I'm only an hobbyist in this stuff).
Lattice don't seem to have much themselves that looks suitable for a beginner, and most of the things you will find on the web are more targeted towards Altera or Xilinx. Any general CPLD, VHDL or Verilog guides should be largely applicable to Lattice parts though, even if produced by another manufacturer. The principles are still the same. Just use them in conjunction with the ispLever help and the part's datasheet so you know your part's capabilities.
This might be useful:
**broken link removed**
Hopefully, someone might offer some more specific advice...