I assume you have an Android device. Once you have the cable connected find your MyFiles you should see your camera or your card, if you're using a card reader, listed in my files just like you can see your SD card you have in your phone, that is assuming your phone has an SD slot. Alternatively, you could remove the SD card currently in phone, again assuming your phone accepts SD cards, and put your SD card from your camera in the slot by passing having to use a OTG cable. No matter what you use you have to access the MyFiles app to see the card. You can also open LR mobile and open the SD card from within LR.
"In the End, we will remember not the words of our enemies, but the silence of our friends." ~Martin Luther King, Jr.