The screenshot below shows where to click in my wallet to power up

After clicking , I will be taking to this page. see below

After my username, the column bears amount is the column I write the amount. I put 0 because I only have almost 0 steem in the wallet.

Then below where it is written power up, which is highlighted is where I will click to power up, converting the steem I put in the column.

Regards
@ngoenyi