indicate the temp as color on the bar make the hammer so ua can hit too hard and find some one in ya areia to let ya watch and ask questions oh and light level in the room determines the color brightness
id recomend useing a gas forge in the game for simplicity ya have to manage the preshure and wach propane levels but it would simplify youre life alot (fewer varibles than a solid furl forge)
in smithing ya can get hurt ad in scale and make them chose the tongs it will let the metal fly off and get lose every so often
make them make their own tools or buy some
start off with a campfire a rock and a hammer and let it grow from there
ya will be suprised by how complex this can get fast