There are 3 main steps when brewing, below, provides some more information for each one of these. 

Mashing

Crushed malt is mixed with hot water to create a mash. It is stirred for a controlled time at a controlled temperature, allowing natural enzymes to convert the starches in the grain to sugars.

Mashing creates a sweet liquid called wort which is lautered (strained) from the malt and sent to the brew kettle where it is boiled with hops. Homebrewers can skip the mashing process by using malt extract.

Boiling

Wort is brought to a boil in the brew kettle. Hops are added at various stages of the boil to provide bitterness, flavour and aroma, that balance the sweetness of the malt and add complexity. Boiling also serves to sterilise the wort and to evaporate off-flavours.

Fermenting

After the wort has cooled, it is transferred to a vessel called a fermenter. Yeast is added to the wort to convert the sugars into alcohol and carbon dioxide. Depending on the style of beer you are brewing, fermentation can last from 3-4 days to several months to complete.