Step 1. Open an investment account (I use Vanguard).

Step 2. Make an initial investment into one of their low cost index funds. Cost is defined by the expense ratio on the product (most of my money is in their Total Stock Market Index Fund. Also some in their Target Retirement 2060 fund).

Step 3. Make additional periodic deposits into the account. Don't pay attention to what is going on in the market on a day to day basis. Just contribute regularly. For me, I take about 35% of every paycheck and toss it in the Total Stock Market Index using the Vanguard app. Takes 30 seconds.

Step 4. There ain't no step 4! Just let your money ride. Remember this phrase "Time in the market is better than trying to time the market". All that trying to find the best time to get in or hunting for the perfect companies to invest in is not worth the effort, in my opinion.
Just get your money in the overall market and let it ride