LaTeX is perfectly suited to for writing scientific reports. Examples might include bachelor's, master's, or doctoral theses. Regardless of the report type, the LaTeX commands are always the same.
Before starting your big project, familiarize yourself with the LaTeX typesetting system. Learn it well enough to focus on content without fumbling over LaTeX commands.
Setting up a document edit
Check if there is an official template at your university, department, institute, or school. If there is one, consider using it, if it's updated and you don't care about potential downstream issues and how it works. A good template should contain a proper copyright note, a support email address, documentation and a proper license.
If there is none, you have to set up your own document. All you need is the stuff below, paper size, font size, headers and footers, everything is taken care of by LaTeX defaults. It is the most basic template and you can change every aspect that you want to change relatively easily.
You will notice missing packages as you write, don't invest too much time at the beginning. Your preamble will grow a bit over time to customize the layout or add packages for comfortable input of units (for example).
Can I use the template of a friend or one I found online? edit
If a friend of yours wants to give you their template, it is a very nice gesture. Say Thanks, but no, Thanks. You won't believe how many strange things are in there without them even noticing it. All those are little tripwires that you don't want in your document. Unfortunately, the same is true for many templates you can find online.
Further reading edit
A short introduction to LaTeX is a free e-book about the very basics. It was translated in many different languages.
LaTeX to write a Phd Thesis is a free e-book that you can consult. It has some valuable tips.
Getting Help edit
If you have trouble, you can always get help.