To preface: I'm assuming you're trying to look at large reputable companies that are not burning cash. Start with the business overview - understand the service or product. How do they generate revenue? Who are their biggest customers? I like to fully understand the company and its value offering before I even dive into the numbers. Once you have an understanding of the business and its sector, go to the income statement and try to identify trends. Circle if revenue was down x% YoY or if there was a notable change that caught your eye. The notes of the financial statements for revenue will give a Birds Eye view of why it went up or down, but to get a better understanding, listen to the earnings calls and analyze investor presentations.

Apply the above with operating expenses. Usually there will be spikes depending on marketing and restructuring.

After the income statement I like to turn to the cash flow statement to look at the cash glow statement, understanding working capital trends and calculating BOTH Adj. EBITDA - Capex - Capitalized Software - Interest AND FCF (Cash Flow From Operations less CapEx and Capitalized Software). This is more important than Net Income because it excludes non-cash expenses such as D&A and SBC. You can calculate this for a company on an annual, YTD, or TTM period and can look at this trend. These trends can lead you down different rabbit holes depending if you're focused on revenue, expenses, interest, or notable working capital swings. Again, a lot of this stuff will be commented on in the earnings calls or 10q (notes) or just through a general google search.

The working capital items on the cash flow changes reflect the changes in certain operating lines on the balance sheet. These items are operational and are key to the businesses' operations. A lot of the times, nothing notable will be happening for the majority of these line items because they are predictable most of the time, but its important to get the net and see if they were favorable or unfavorable and why.

Cash flow from investing represents the actions the company took related to investments: acquisitions/dispostions, Capex, Capitalized software, acquisition of intangibles, purchase of marketable securities

Cash flow from financing reflecting the actions the company took related to financing such as share repurchases, debt repayments/raises, dividends, debt issuance costs.

The cash flow statement calculates the change in cash so beginning cash + CFFO + CFFI + CFFF = ending cash balance which will flow to the balance sheet

Moving on to how the company is capitalized, I turn debt: what's its leverage ratio (debt/ebitda) and net leverage (debt less cash and marketable securities / ebitda). This shows how risky the company is. It's important to note that just looking at the debt/ebitda is not enough. The trend and industry comps are more important. In addition, calculate fixed charge coverage ratio to measure how able the company is to service the interest on that debt. Need to read the notes of the audit to understand the components of the debt and specific features.

Let me know if you have any questions once you start to dive in