Thulasi devi married Lord Krishna on the shukla paksha dwadasi thithi of Karthika masa before full moon. Uthana means waking up from sleep. Lord Vishnu was taking rest(sleeping) during chaturmasa and gets up on the uthana dwadasi day evening.
We all know that basil ie thulasi with all its medical properties is considered very sacred. All the ladies start their daily puja after worshipping thulasi devi. In madhwa community uthana dwadasi is an important puja which is performed in the evening.
Amla(nelli) branch is kept in the thulasi brindavana and puja is done in the evening with possible madi. Lord Vishna comes in the name of Damodhara in the amla plant on this day. We have to take 5 big amlas and scrap inside. We have to pour ghee inside it and keep hoo-bathi for taking aarathi. We have to tell archana, slokas and songs on damodara and thulasi. Kosambari and laddu are prepared as neivedhya & given to sumangalis along with thamboola.