Bottom bracket for Bottechia 989
You have a sealed cartridge type bottom bracket. You can take it out but you can't disassemble it, clean or service the bearings. If the bearings are running smoothly without excessive resistance leave it alone. If you do need to replace it new units are not particularly expensive.

The cranks fit on square taper or spined interfaces on the axle. The bolt in the crank pulls the crank onto the axle. 

To get the cartridge out first you need to remove the crank bolts and use a special tool to pull the cranks off the axle. The cartridge itself threads into the shell in the drive side and is held in place with a locking cup on the non drive side. You need another special tool to interface with the splines in the cartridge body or cup and a large wrench to unthread them from the shell. The drive side thread is left handed.

Chances are you have a standard cartridge with ISO shell threads, and JIS square taper axle. See https://www.sheldonbrown.com/cribsheet-bottombrackets.html and https://www.sheldonbrown.com/bbtaper.html.

To replace the cartridge you need to know it's for a road bike with a 68mm wide bottom bracket shell (check this) and the axle length. Axle length is critical to make sure the chainrings are spaced from the centerline of the bike correctly.