Within the manager, click on Add a block then Add a column. On the left, activate the image widget and on the right activate the visual editor widget (to insert text). Click on configure to upload your image or select the image you want to use into the image widget and write text on the right in the visual editor widget.
You can then change the margins, by changing the width of your columns. This is displayed in percents. If you want to imitate the page layout just below we have, with the image and the text side by side above we used 75% for the column on the left and 25% on the right. These percents can be changed, you could also put the image on the left and the text on the right. The choice is yours, we have just simplified the process.