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Welcome to the forum.

Hi and welcome to the forum.

Your editor seems to be absolutely pointless. It doesn't show you the real error message.
Open the log file yo see which vommands are undefined.

Also, why not asking the journal editors directly if their template is broken?

Your post is very unclear.
What is your question?

To get a good looking table that is ready to be published, you need some manual labour.

Where is the problem with the table shown? It is very simple. Have a look at package booktabs.

Please post code as text that we can copy and compile, not as a screenshot.

Edit: i just looked around and found the template on github. I advise not to use it at all.

LaTeX found an error. Fix that.

How does the console output end? What is at the bottom?

Welcome to the forum.

Just copy the template to your desired folder; so that cls and the main tex file are in the same directory.