For the summary as per your requirement create a block and put a item in that block residing on the same canvas.
Then set below mentioned BLOCK property for newly created block:
- Single Record: Yes
Then set below mentioned ITEM property for the newly created item:
- Data Type: Number
- Calculation Mode: 'Summary'
- Summary Function: 'Sum'
- Summarized Block: Block you created
- Summarized Item: Item you created
I hope it will work for you, I have tested and working fine.