since you are new to mining
i suggest you should not go 12 cards mining rig
first buy cheap used PC with good high wattage power supply ( 750w minimum )
buy 2x used cards ( 1x nvidia & 1x amd )
then put your hands on building it and do some mining and learn how to manage it

then do the calculation on this PC in term of profitability and electricity

after that you decide if it is worth it or no

as most of guys said
selling these cards better than mining on them
but if u want to keep them
i would suggest to go with one of these

Betterhash - a good alternative to nicehash miner

Awesome miner - it is just a mining manager help u to connect to other pools and profit switching pools <--- Best in my opinion

in term of electricity consumption
i would go with Nvidia mining cards
P106 - 22mh on ETH @ 80w cost ~$100
P104 - 35mh on ETH @ 100w cost ~$200

but consider the resale value of this cards will be lower than normal cards
beside that , Nvidia support more algo's
that's my opinion from mining perspective

thanks and regards

there are some other online shops selling it for around $200 - $250 brand new but different brands
gigabyte and evga

thanks for your great work @phoenixminer

would u mind to give an example on how to use the new options?

thanks and regards