How can i add second block container on the left side?
Design 1181 does not have a second block by default. You can add a new block in Control Panel > Design customization > Global blocks, customize it, and then add its code (e.g. $GLOBAL_BLOCK$) to the website templates. You will also need to customize the templates for the new block to look properly.
If you are not very familiar with HTML, I would rather suggest that you choose another design that has two side block containers by default.
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