As with many other Microsoft applications, there are several ways of doing things.
Excel’s commands can be accessed through the menubar at the top.
Clicking the righthand mouse button, while the cursor is in a cell, brings up a mini menu of mainly formatting options.
There are keyboard short cuts (such as [CTRL] and [SHIFT] and $ applies the currency format to the cell(s) that you have selected.
There are a range of toolbars (normally shown below the menubar) can be added or removed depending on what you use Excel for. For example, there is a formula auditing toolbar, which contains comands that help find errors in spreadsheets. Any of the toolbars can be customised and new toolbars can be created.