maybe I am getting brain freeze but when I am trying to make this assembly why is it coming up in Base Unit and not in consumption unit?

Work orders (assembly itself not components) are always in base units. Can't be edited.

but how do you make 100 KG of something then?

Depends on your conversion rate in the Units of Measure. 100 x 1000 = 100,000 grams

you need to do the math to calculate how much you need for each G then when you make a BOM rev then?

Yeah both will work but you can't change the base unit for an existing UOM if I am not mistaken. Has to be a new one then

yeah we will need to create new item or change the UoM

Be careful, you always want the Base UoM to be the smallest for that item if you're doing converstions. Otherwise you'll likely run into rounding errors in inventory. Consumption UoM is for if you're consuming an item as part of a BOM, not making the item.

Yeah that’s why I have gram as base unit but I need to make things in KG, so how should I go about?

Do you actually transact anything in grams for anything utilizing that Unit Type? If not, does having grams serve a purpose?

Nothing in gram, it’s on the UoM because of raw materials, make in KG

So, it sounds like you use the Unit Type on other items (materials) and actually use gram for that on receipts or as the consumption unit. In this case, you could create a separate Unit Type where kg is the smallest uom.

hmm so we need two different UoM, one for Raw Material and one for Finished good for Weight

That's a potential solution, yes. Unit Types are definitely an item where I spend extra time strategizing with customers.