Acer Altos G710 - Manual (Page 60)

3 System upgrade 50
3 Install a hard disk on the hard disk carrier (1), then secure it with
the four screws you have removed earlier (2).
4 Insert the hard disk carrier into the cage with the lever still
extended.
5 Push the lever back until it clicks into place. Make sure that the
drive is properly inserted before closing the lever.