The upgrade process is performed in two stages. The first stage is to load the installation package into your website. The second stage runs the Kunena Installer program.
Load the installation package into your website
Step 1: You need two browser windows:
(1) Joomla Extension Manager on your admin site (see image on the left)
(2) Go to the Kunena download page, locate the image on that page that looks like this: Image:kunena_download.png
Step 2: Get the location of the download URL.
Right mouse-click the image on the Kunena download page, and choose "Copy Link Location" from the popup context menu that appears. For K 2.0.0, this should look like this:
Step 3: Paste the download location on the Install from URL link.
On the Joomla Extension Manager page, press CTRL-V to paste the link you copied in step 2 above, into the Install URL input box.
Step 4: Begin the installation.
Press the button labelled Install (that's the button to the right of the Install URL input box where you pasted the link to the Kunena installation ZIP file).
Run the Kunena Installer program
You should now see a screen, similar to the image at the left. Click the yellow button labelled "Migrate Kunena 1.x.y" that is appropriate in your case. Do not press the Green button; this will hide your old forum data. In a few seconds you should see the progress of the installation updated. If you see a screen, similar to the image at right (with OK against each item on the list) then you have installed Kunena properly. Finalise the installation by pressing the Finish button on the top right of the screen.
Note: You should only use this procedure one time, when you are upgrading from an older version of Kunena or Fireboard.