Need some help with posts' template editing

[my add]

I have a personal blog (https://estrelapedra.blogspot.com), and I am changing its template, but since I installed this new one my posts lost its formatting, it seems the template is forcing my posts to follow its rules.

I want it to look like on the left – http://imgur.com/a/TBswR

I believe I need to edit something on the html template, but I don’t understand a thing.

Thanks for your attention.

[Author]

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