The diagram illustrates the process that is used to build an igloo from snow.
There are five main stages in this process, starting with finding an area covered by hard-packed snow and culminating in covering the entrance hole with snow blocks.
As can be seen from the process, after a surface of hard-packed snow is found, a snow saw is used to cut large blocks to the appropriate size to build the base. The edges of the blocks are then smoothed with the saw and are placed in a circle, and a hole is dug under the wall to make an entrance. Next, a slightly over-sized block is precisely shaped and placed on the top of the igloo.
Out of the remaining steps, snow is shoveled onto the outside of the igloo and is packed into all crevices while the internal surface of the igloo is smoothed by hand. Any excess snow is also removed from the inside of the igloo. And finally, a hole is dug in the shape of the entrance, and is then covered with snow blocks to complete the igloo. 
The diagram illustrates the process  
that is
  used
 to build an igloo from snow.
There are five main stages in this process, starting with finding an area covered by  
hard
-packed  
snow
 and culminating in covering the entrance hole with  
snow
 blocks.
As can be  
seen
 from the process, after a surface of  
hard
-packed  
snow
  is found
, a  
snow
  saw
 is  
used
 to  
cut
 large  
blocks
 to the appropriate size to build the base. The edges of the  
blocks
 are then smoothed with the  
saw
 and  
are placed
 in a circle, and a hole  
is dug
 under the wall to  
make
 an entrance.  
Next
, a  
slightly
 over-sized  
block
 is  
precisely
 shaped and placed on the top of the igloo.
Out of the remaining steps,  
snow
  is shoveled
 onto the outside of the igloo and  
is packed
 into all crevices while the internal surface of the igloo  
is smoothed
 by hand. Any excess  
snow
 is  
also
 removed from the inside of the igloo. And  
finally
, a hole  
is dug
 in the shape of the entrance, and is then covered with  
snow
  blocks
 to complete the igloo.