@sandij- Hi. Tinctures usually come in a bottle with a dropper. But the dosage and amount of CBD in the oil can change with different companies and different grades of the oil.
@betsyjane- There is no standard as yet for CBD oil, no set dosage. The only advice that I can give you is to first read the posts here and see what others have done. The contact someone at the company you chose to answer questions.
I use CBD oil but I am going up in dosage and there is also a small amt of THC in it which will also increase.

When I first started my local dispensary suggested 10 mg CBD oil to start with. Take it once or twice a day at the same times and give it several weeks to work. You can google about how to use the drops.
Do you personally know anyone who takes it who you could ask how they make their decisions?