Of course not! You should read and understand the paper. Then put the paper away and explain its contents in your own words and with your own structure.
In addition to that, here are some ideas what you can do to set your essay apart from the original paper:
- Better explanations: Conference papers often suffer from space constraints and may be forced to leave out explanation. Your seminar paper can be much more helpful to the reader trying to understand the content. Give explanations: why is this definition/theorem/algorithm the way it is?
- Better proofs: You can add further explanation to proofs (or even write a proof they omitted).
- Simplify: Come up with simplified versions of X and explain how to get from the simplified version to the fully-fledged version.
- Related work: You can explain and compare related work (especially for works that have not yet been available when the paper was first written)
- Examples: Help the reader understand by giving concrete examples. For example: what's a useful application of Theorem 2? How does this complicated algorithm work for simple inputs?
Your seminar essay should be comprehensible for students similar to yourself (before you started working in the topic).
When evaluating a seminar essay, we mostly ask ourselves the following questions:
- Is what is written in the essay correct?
- Do you demonstrate a good understanding of the topic in your essay?
Note that just paraphrasing the paper does not demonstrate understanding. You need to be able to explain the content in your own words. A concise and comprehensible explanation is a good demonstration of understanding.
While not our main focus, an excessive amount of typos, grammar errors, bad citations, etc. in the essay can negatively affect its evaluation.
Your seminar talk should be comprehensible for the other seminar students.
The seminar talk is another chance to demonstrate that you understand your topic. Note that this does not mean that you should put the most complicated content into the talk. It is much more impressive to explain your topic clearly and comprehensibly than to spend the time showing overly complicated stuff that nobody has a chance to understand. When in doubt, favor a clear explanation of just a subset or simplified version of your essay content over cramming everything into the talk.