So you want to install OpenWrt/LEDE on one of your devices.
The following preparation is recommended, before flashing OpenWrt/LEDE firmware:
Don't rush the installation, take your time. If something seems weird during installation, find answers first before continuing.
Have your device's precise model name at hand (so you are able to select the correct OpenWrt/LEDE firmware)
Have your devices's documentation at hand, on how to flash new firmware
When installing and configuring OpenWrt/LEDE on your Internet router, your Internet-access will obviously be offline for a few minutes. Please ensure that you have all required information offline or have backup Internet access at hand in this time.
If you have any questions:
Browse this (OpenWrt/LEDE) site, especially the user-guide section.