help me patching macos Sequoia

hi, i’m new to OPLC and i’m trying to patch macos Sequoia on a iMac9,1 (early 2009), but every time i try to install Sequoia it changes and finally i get the error: “error during the update”. on this machine i have already El Capitan, maybe is this the issue? anyway this is the fifth time i tried to install sequoia… meanwhile i try another time. thanks