hi,
i asume you want to use the on chip memory.
first, the lpm rom/ram functions are not to be used any more. you choud use the altsyncram object.
The mif files are louded in to the ram cels(m4k, m9k,...) at configuration time, they are compiled in to the sof or the pof file. these files can be etided via the quartus interface.
Reading and writing is very easy, the data is stored or writen to (depends on wren ) wen the block get its clock signal.
Here is a link where you can find al the info needed
http://www.altera.com/literature/hb/cyc/cyc_c51007.pdf hope this helps you out.