Clicking on the "Add Media" button will bring up a window with all of the images that you have previously uploaded.
If you have already uploaded the image: select the image you want to insert by clicking it.
If you have not yet uploaded the image, click the “Upload Files” tab and upload your image. It will automatically be selected when the upload is finished.
Once you have selected the image, you can adjust the "Attachment Details" and "Attachment Display Settings" on the right-hand side of the page.
The "Attachment Details" section will let you insert some optional fields such as "Alt Text".
The "Attachment Display Settings" section (located below the "Attachment Details" section) will let you:
Click the "Insert into Page" button to insert the image.
you have inserted an image, you can edit its alignment, size, etc. by
clicking on the image and then clicking the edit icon.