I don't know what to do please guys help me.I says a message ''Now send the package you want to apply to the device with adb sideload filename...''Please help.How can i get back or something else.Lenovo tab A-3300
Just keep clicking back and reboot into the system.You are in recovery a place in which you can use Android debug bridge to retrieve files from your computer even when your phone has been bricked.
Like any other app just keep tapping back.choose to reboot into the system.
If this has not helped plz send a screenshot as I don't have this device and every recovery is different.