Symbols and when to use them?

Hi Leonie, Thank you for your post, welcome to the forum, I hope you enjoyed your Excel course, in answer to your question, more info about Formula Operators; on the Formula Toolbar, you will notice a little button with fx on it, this is the Insert Function button, clicking it will open the Insert Function dialog box, if you wish to perform a particular task, or see how a Formula should be set up (its syntax) this box will assist, there is an additional link on the box, for a selected function, you can click the 'Help on this function' link at the bottom of the box to open a help pane which explains it in greater detail.
Your question also says Symbols and when to use them?
The main operators are [+ - * / > < <> >= <= ( ) !] in addition you have [and, or, like, and not like] for text, using them depends on the calculation you wish to carry out, remember when you create a formula that Excel carries out its calculations in a particular way, the acronym BODMAS which stands for;
B= Brackets (parenthesis) ()
O= Ordinals (to the power of) ^
D= Division /
M= Multiplication *
A= Addition +
S= Subtraction -
This is the order of calculation;
Further thing to remember is that if you bracket parts of your formula Excel will undertake the deepest bracketed part first and then work its way out.
I hope that has helped in a very small way, as there is so much that can be covered on this subject, if you have a more specific question please come back and we will discuss it, if however if this has answered your question, please click the Resolved link, look forward to seeing you on the forum again, best regards Pete.
Pete Emmerson - Microsoft Office Specialist Master Instructor.