The sentence you've given doesn't really make sense.

Your understanding is somehow correct.

It means 'keep the question about exceptions in your mind and we're going to focus on these ones (hold it for a later time -- we will explain it later)'.

Furthermore, it's poorly punctuated. The 3-4 sentences are written as if they were 1 sentence.

The sentence you've given doesn't really make sense.

Your understanding is somehow correct.

To me, it means 'keep the question about exceptions in your mind and we're going to focus on these ones (hold it for a later time -- we will explain it later)'.

Furthermore, it's poorly punctuated. The 3-4 sentences are written as if they were 1 sentence.