Mushrooms

Has anybody got any tips for growing mushrooms?  I have some grain spawn, some well rotted horse manure and a box. That's as far as I've got at the moment, I was given the spawn by a fellow allotmenteer and he said I should sprad the spawn on top of the manure and cover it with damp newspaper, another person told me to rake the spawn into the manure. I'm comfused now   Please help!!

Thank you  Sunshineband. I will put it all together today and in ten days time I need to put some casing on top. I do hope I get some mushrooms......  I'm excited!!