Simple process but DO NOTE the warning against using "ultra-pasteurized milk".
Use Whole Milk, not 2-3% milk... The milk fats and proteins are what make cheese...
http://littlehouseinthesuburbs.com/how-to-make-ricotta-cheeseYou really should have a food thermometer for this, but it can be made without using one, if you're careful and observant.