What are PTR ads?

PTR ads or PTRA means Paid To Read Ads.

You can find them here: log in to your account, go to Earns -> Paid To Read ads.

They are similar to PTC ads (those are under View Ads).

You will click on an ad in Paid To Read section, then a new window will open. Some text ad will appear there. Wait some time (as the counter says) and then click on Continue to the Site button. The rest is same like with PTC ads (let counter go to 0 and then choose the correct number of the 4 numbers there and click on it (as "Click x" says).
Let it redirect you, then you can close the window/tab.