You cant load the wmb levels in free Lite-C,
so you need to manually create your level out
of entities (Models, terrains, etc)
You can start out by creating the levels "by hand" in the code,
and if you are more experienced, using your
own import-function for the positions of the objects.
You could even create your level in Excel, and
export the tables to a textfile, wich you use to
place the objects.
There are many approaches I could think of, even using
a tile editor.
But if you cant get anything like that to work, just buy
a basic version of game studio, then you have WED...