When editing your profile the page will be displayed the same as if you were viewing your profile but a few additional options will appear on the screen.
Editable text areas will highlight in red when you hover over them and will allow you to make changes once you click on the area:

Clicking in the highlighted area will allow you to edit the contents

You can use simple formatting for your text bold and italics, you can make lists or numbered lists and you can insert hyperlinks, images or YouTube videos.
You can choose to hide individual text areas if you want to keep the content but don't want to display it at the moment. To do so, toggle the switch to the right of the heading you wish to hide, toggle it back to display it.
Once you have finished making changes to your text and you are happy you will need to click the green 'Save Changes' button at the top of the profile page.
Insert a hyperlink into your text
You can add hyperlinks to your text by first selecting the text you wish to link and then click on the 'Insert edit link' button in the toolbar:

This will bring up a dialog box allowing you to enter the link you wish to use:

Enter the link in the Url text box and click 'Ok'.
Inserting images
You can add images to your text by first putting the cursor where you want the image to go and then clicking the 'Insert edit image' button on the toolbar:

This will bring up a dialog box:

If the image is located on a different website then you can put the link to the image file in the 'Source' box.
You can also choose to upload an image from your computer, click the browse icon:
This will open the profile files browser. Each profile has its own storage for images and files.

Click the upload file button to add the new image

Either drag and drop the image files into the dotted area or click in the area to upload files via a dialog box.

You can add more than 1 file at a time if you wish, once all the files are in the area click on the 'Submit files(s)' link and your files will upload to the server.
Once you have images available to use click on the image you want to insert into your text and the 'Source' box will have the link to the selected image. Click 'Ok' to insert the image into your text.