Step 1: Create a group with query in Data Model, remember 
this query should have atleast three columns for Row, 
Column and Cell value. and Four if you want to create Group 
Matrix Report.

Step 2: Drag Column you want to act as Group Header from 
Group, then drag Row Value and then Column Value.

Step 3: In Data Model window you will find icon for Cross 
Product in tool box. click on that, then Drag the Mouse 
pointer keeping the left click pressed over the group of 
Row and Column values selected by you in step 2.

Step 4: In Layout Model window, Create Repeating frame then 
create one more repeating frame over the previous one but 
at this time please change the property of repeating frame 
as PRINT DIRECTION : ACROSS. Then select both the frames at 
once and then go to Menu Insert>>Layout Matrix, by doing 
this you merge two frames, now in the intersection area of 
this two frames create one more repeating frame.

Step 5: In the merged frame the one which is Print 
Direction down will display the rows, one with print 
direction across will display the columns and intersection 
will display the cell values. Accordingly assign the source 
for all three repeating frames and create fields in those 
frames and give the desire sources.

Step 6: Run the report