What is the you're facing (e.g., bricked, want an update, unlocking bootloader)? Do you have OST LA tool already? Once you provide that, I can give you the specific steps!
The official Android ROM provided by HMD Global, often used to unbrick or restore the device.
The ROMs (ES2) are compatible across several variants (TA-1049, TA-1057, TA-1063, TA-1070, TA-1074) [1].
Get the appropriate stock firmware for your specific TA-variant (ES2).
You will need MediaTek USB VCOM drivers installed on your PC to flash files. Installation Method (Stock Firmware)