If you don't understand what @Sshannon said, start with the instructions below. When you are done with that, go back and re-read what Steve wrote. By that time, you should be able to program your UV-5R. If not, let us know exactly what problem you are having.
For the AT-778UV:
First, using the OEM software(this can't be done in CHIRP) click on the Model menu and select Model Information.
Make sure Band 2 is selected.
After setting the band, double click on a channel/memory space in the grid to get to the settings for that line.
Your results should look like this:
In CHIRP, it should look like this:
Read this to get a better understanding of CHIRP, especially the Tone Mode column.
EDIT:
I forgot to mention, one of the strengths of CHIRP is that after programming your repeaters in one radio, you can copy the lines and paste them into the file of other radios. If you have multiple repeaters and multiple radios, this will save you a lot of time.
NOTE:
When using CHIRP, first read from the radio and save the file. You will need a different file for each different model of radio. You can't load the AT-778UV file into a UV-5R. There is a lot of other specific things CHIRP has to know before trying to write to a radio.