Help on flashing Samknows whitebox 8

Hi.
Due a replacement I have an unused sk-wb8 and I need help with flashing.
The instructions at wiki.openwrt.org/toh/samknows/sk-wb8 are too critical for me.
I have the usb to serial adapter, putty installed and the board open, but I can not get into failsafe mode.
Any step by step for beginners to start the process ??