If your SD/TF card is not clicking and locking in place then you can check the following things:

1. Is the SD/TF card in the right way?

2. Is the SD/TF card damaged or worn where the cutout notch is on the side? (this is what locks in place)

3. Check the SD/TF card mount, on the right-hand side is a metal prong that should be bent slightly inside of the mount. This is what locks against the SD/TF card notch cut out. (See image where the screwdriver is pointing for the metal prong locking mechanism).