How Can I identify the exact issues & where the issues are

Try checking articles related to this.  I found this though it is not the IIS template.  Might be useful.

support.solarwinds.com/.../AppInsight-for-IIS-is-Unknown

https://support.solarwinds.com/SuccessCenter/s/article/Appinsight-for-SQL-Monitors-in-Unknown-state?language=en_US

www.youtube.com/watch

It's also important to know that "unknown" can mean different things depending on the entity involved and the product reporting it. These are great articles if the issue is within IIS. 

As for the basics about figuring out what the problem is on something showing critical or warning, you want to click the entity to go to the entity details page and "follow the breadcrumbs" for where and what the issue is. Is it capacity? is it hardware? You will want to examine the different detailed resources to find where the problem is. You can also hover over the entity in the All Nodes view, and the tooltip window that pops up may show you what the problem is, but that's contextual to the entity and problem so you may not see it in a preview. In that case "click and drill" down into the entity to see the details. 

Hope that helps too!