I am a 17 year old student
And I have this task to
Analyze an interim report of a company
To see if I should or not buy their bonds.
I need some major help, since I have no knowledge
About investing.

Thank you so much.

In reality, a project like this is probably more interested in your ability to analyze the stability and cash flows of a company than in knowing anything about investing. The bonds are probably just an excuse. You've (I assume) been learning financial analysis and it's not uncommon to then get a project to use what you've learned to analyze a company -- with an excuse like would you invest in it?

Not something easily answered. Not only is it too involved and complicated for anyone to give an easy answer, but also if you've been learning this stuff, they may want you to use some very specific things you've been learning and no one can know what that is. Not to mention that we wouldn't know the context of the project -- I don't even know if this is a finance class. If you've been doing a chapter(s) on this stuff, then you need to be looking at the types of things they were doing, what ratios and other financial figures they were teaching you, etc.

But, here's a whole big thing with lots of equations and some info on what they mean:
Investopedia.com: Financial Ratio Tutorial
Bear in mind that these equations can have slight differences to them -- if something is different than your text (or what an instructor gave you), then use the book.

(This seems a bit much for a 17 year old. Please tell me that you've actually gotten into college young and that they aren't requiring this for high school. Oh my.)