You listed Debian in the required skills. Can you confirm that your server is running Debian? If so, what version (8.x, 9.x)?
I am installing a test version of Koha on my own server now - and will update this bid once I have it ready. I will test on a server running Debian version 9 - probably using Koha version 18.05 (current stable version).
In the meantime, please note that this bid is PROVISIONAL. (I may need to adjust the price and / or timeframe.)
I am based in Ireland - approx. two hours behind Kenya.