Lower Third words for church

We currently have an ATEM switcher and just switch between our propresenter slides and our camera. We are hoping to move the words to the bottom third of the video versus switching out of the video. I have seen where the words just go in the bottom left corner, but we were hoping to have them go in a banner on the bottom. Is is possible? If so, how?

Our church adds lower thirds for names and lyrics overlaid on the live camera feeds using the ATEM chroma key.
Our setup: In ProPresenter all slides have a uniform blue background, we use a template in Pro to make all of our text white and a specific size at the bottom of the screen, with a semi-transparent black banner behind it. We then convert the HDMI output from the ProPresenter Mac over to SDI (we are using the ATEM 4K, so no HDMI inputs) and send into the ATEM. Then, within the ATEM we set that particular input to be a chroma key and sample the blue color that is coming out of Pro. From there, when we enable the key, the lower third text looks perfect overlaid on the video (there is no blue, and the black banner correctly appears semi-transparent, which helps to keep the white text from blending into the background video).
There are other, better, ways to accomplish this, but this is the best method we have found without any additional equipment and with a single output from the Mac. An alternative would be to have two outputs (one for Key and one for Fill), but that requires additional BMD equipment between the computer and the ATEM.
I hope that helps to answer your question.

Tim

Does your ATEM switcher use SDI or HDMI?

If SDI is available the "best" way to do this is to use one of the BMD Decklink or UltraStudio products combined with either the appropriate PP6 add-on modules (SDI and Alpha Keyer) or the new PP7 to output SDI fill and key signals to the switcher. You can then use the DSK on the switcher to layer the PP output over top of the camera signal.

An alternative without using the extra hardware (and modules for PP6) is to use a luma key. For this, you would not be able to use black on the projected part of the slides. You would use black for the transparent areas - give the slides a black background - and set the keyer to use a self-key so that the black areas become transparent, letting the video show through. If you want "black" text you could use a very dark gray that visually looks black but is sufficiently brighter (technically) to not get knocked out by the keyer on the ATEM.