I was getting frustrated just as you were trying to figure this out. Here's what to do, step-by-step:
1) Select POLLS
2) Select ADD NEW
3) Create your poll, select your design, and then select SAVE POLL on the upper-right corner.
4) On the left side, select POLLS and then select EDIT.
5) Mouse-over to the poll you want to use and select SHARE-EMBED.
6) Highlight and select everything in the WORDPRESS SHORTCODE field, including the open and close brackets.
7) On the left side, select APPEARANCE and then select WIDGETS.
8) Drag the TEXT widget to your sidebar on the right side of the screen.
9) Click the down arrow button on the TEXT widget.
10) Enter a name for your poll in the TITLE field.
11) In the box below it, copy the contents of step 6 above.
12) Select SAVE.
13) Refresh your site, and you should see your poll.
Hope this helps!!