How do you warm up frozen BREAST MILK?

PureHonesty
Curious on the best way I exclusively breastfed for 16 months no bottle no pumping it was hard I didn't work the whole time.. This time I have a breast pump and plan to go to work within 3 months ? So doing it a bit different this time .best suggestions you have for milk storage and warming it such as by it self for a day or warm water in a bowl or a bottle warmer ect?