Archer C5 & TL-WR902 AC 750 wireless travel router

[Elly]

Kindly assist me on how I can go about and install openwrt on the aforementioned routers for them to work properly with 3g/4g lte dongle as in my area i don't foresee installation of fibre optic in the near future. I will request the replies to in English otherwise thanks in advance as always I do appreciate your cooperation