To save a program to card :
Switch to Program Mode (I forget exactly what it's called). Type in the program as usual. While still in program mode, feed a card into the reader. If the program is too long to fit on one track of the card, the machine will prompt with Crd (IIRC), then feed the card in the other end first to record the second track. An HP97 program will always be short enough to fit on one card (2 tracks).
To read the program back in again:
Switch to run mode and feed the card in. Again, if there's a second track, the machine will prompt for it.
To save numeric data to a card:
In run mode type in the data and STOre in the registers. Then press WDATA (I forget the exact name, it's almost certainly a shifted function) and feed in a card. If you have non-zero values in the secondary storage registers, it'll prompt for a second track as above
To read the numeric data back in :
Just pass the card through the reader in run mode.
The user and service manuals for the 97 are on the MoHPC CD-ROM set, BTW.