When you copy the website link, then you click to reply to a post, you will see on top the white smile, below it look like a earth ball, click that, paste the link on there then click OK, then press space bar after html, then add your own words, then click submit
You can use this thread to practice. Let me try again ha ha.
other way... use either Quick Reply box or Post Reply
either you type or find a text you want linked then highlight that part of text then click the Link button above the text box (the Link button is a Earth with chain at bottom although you can hover your cursor over the icon for tooltip to appear to tell you it is "Insert Link" ) a box will pop up for you to type in url then press ok...