To create a logo with a transparent background please try this approach:
1) Open you canvas settings (while your logo is open). You can find this by clicking the round "Logo" button at the top left of the program.
2) Click the Preferences button at the bottom right.
3) In the Canvas Output section of the Preference Panel, choose the Transparent option and click the OK button.
4) Your canvas background should now show a checkerboard pattern.
5) Now click the round "Logo" button again and select Export "For Print Use".
6) Select the png option, click Next.
7) Leave the "None" option under Interlaced selected; the Transparent checkbox should be already checked and grayed out. Click Next.
8) Choose the DPI or Original Size setting and click Next.
9) Under Destination, select the Browse button and choose your Desktop and click OK. The new destination location should now show it will be saving to your Desktop.
10) Click the Export button. Click OK and Finish to complete the export process.
Now go to your Desktop and find the PNG file. When you open this (double click it), the background of your logo should no longer be white; it should now be a light gray. There will be no checkerboard pattern in this transparent image. If you save and then reopen your logo file, the canvas will not hold the checkerboard pattern. You will just need to make sure you export as a transparent PNG in the future following the same steps above.
One thing to keep in mind...many Internet browsers do not support transparency very well (except for Firefox). So, your logo may not always appear transparent, although this does not seem to be the case most of the times.