When you are typing a post, scroll down a bit and you will see a section called Manage Attachments. Click the button and in the new window you will see a button with a green + labeled Add Files. Then you can choose either uploading files from your computer or from the web. After an image has been uploaded, you will see a thumbnail with a check box. Back in the text editor, put the cursor where you want to insert the image. Next, click on the paper clip icon above the text box and select the image that you want to attach by ticking the check box. Next click Done. To make sure that everything looks the way that you want, click Preview Post.