Introduction to Excel

Welcome to your first Excel lesson. Before we touch any formula or click any cell, let's make sure you have a solid picture of what Excel actually is, how it works, and why so many people use it every day at work. Once this clicks, everything else in the course will make a lot more sense.

Excel Is a Spreadsheet Tool

Think of Excel as a very smart digital table. It is made up of rows and columns, and wherever a row and a column meet, you get a small box called a cell. That cell is where everything happens — you type your numbers, your text, your formulas, all of it goes into cells.

Microsoft first released Excel back in 1985. It started as a basic calculator tool, and over the decades it grew into something much more powerful — a full platform where you can store data, run calculations, clean messy information, build charts, and even automate repetitive work. All without needing to know how to code.

Today Excel is part of Microsoft 365, which means it works alongside Word, PowerPoint, Teams, and Outlook. You can run it on your Windows PC, your Mac, or open it in any browser at office.com. Throughout this course we use Microsoft 365 Excel — the most up-to-date version with all the latest features.

The Grid — Rows, Columns, and Cells

When you open Excel for the first time, the first thing you see is a large white grid. That grid is the heart of everything. Let me walk you through exactly how it is organized.

Columns run left to right and are labeled with letters — A, B, C, D, and so on. Rows run top to bottom and are numbered — 1, 2, 3, 4, and so on. Every single cell in the sheet has its own unique address made from its column letter followed by its row number.

The green cell is A1 — Column A, Row 1. The blue cell is B2. The purple cell is C3. Column letter always comes first, row number second.

One sheet in Excel can hold up to 1,048,576 rows and 16,384 columns. That is more than enough for any real-world data you will ever work with.

Here are the key words you need to know right from the start:

Four Things You Can Put in a Cell

Every cell in Excel can hold one of four types of data. This matters more than it sounds — Excel behaves completely differently depending on what type of data is in a cell. A number can be added and averaged. Text cannot. Let me show you all four right on a grid.

Dates are an interesting one. Internally Excel stores every date as a plain number — for example, 1st January 2025 is stored as 45658. Excel just displays it in a date format so it looks readable to us. This is why you can do maths with dates, like calculating how many days between two dates — because underneath, they are just numbers.

Your First Formula

The most important rule in Excel is this: every formula starts with an equals sign =. That single character tells Excel — "don't show this as text, calculate it." Without it, Excel treats whatever you type as a plain label.

Let's start with the simplest thing possible. Click on any empty cell and type this:

=10+25

Now here is where Excel becomes genuinely powerful. Instead of typing numbers directly into a formula, you can point at other cells. Say cell A1 contains the number 10, and cell B1 contains 25. Click on C1 and type:

=A1+B1

Now go back and change A1 to 100. Without touching C1 at all, it instantly updates to 125. Excel recalculated automatically. That live, connected behavior is the whole reason Excel exists — your data and your results stay in sync at all times.

A Real Business Example

Let's make this more realistic. Imagine you are tracking monthly revenue for your team. You have four months of data in column B, and you want the total in row 6. Here is what your sheet looks like:

=SUM(B2:B5)

One formula, one second of work. And if February's number changes next month, your total updates on its own. No recalculating manually, no risk of getting it wrong.

Excel File Formats

When you save your work in Excel, you get to choose a file format. Most of the time you will stick with the default, but it is worth knowing what each one means so you are never caught off guard.

Excel Versions

Not all versions of Excel have the same features. Some of the most useful functions we teach in this course — like XLOOKUP and dynamic arrays — only exist in newer versions. Here is a quick picture of what is available where:

If you are on an older version, do not worry — most of what we cover still works. We will always tell you clearly when something requires Microsoft 365 specifically.

Where People Use Excel Every Day

Excel is not tied to one job or one industry. Here is a quick look at how real professionals use it across different fields. As you go through this course, think about which of these applies to your own work:

Excel vs Google Sheets

You may be wondering — Google Sheets is free and works in the browser, so why bother with Excel? It is a fair question. Google Sheets is great for simple work and real-time collaboration with a small team. But once you get into large datasets, complex formulas, Power Query, Power Pivot, DAX measures, and automation — Excel is in a completely different league.

In most professional workplaces, especially in finance, consulting, and enterprise operations, Excel is the expected tool. Learning it properly gives you a skill that is immediately recognised and valued on the job.

What You Will Build in This Course

By the time you finish all 50 lessons here at Dataplexa, you will be able to do all of this confidently:

Lesson Summary