What's your question? Ask

This article should help: https://www.gardeningknowhow.com/ornamental/flowers/begonia/wintering-begonias-overwintering-a-begonia-in-cold-climates.htm

On average, you would put in about 3-4 plants per 10 inch basket.

This article should help with that: https://www.gardeningknowhow.com/plant-problems/disease/powdery-mildew-homemade-and-organic-remedies.htm You can also try neem oil. In addition to being an effective organic insecticide, it's a great fungicide. Here is more information: https://www.gardeningknowhow.com/problems/pests/neem-oil-uses.htm

Could it be begonia soli-mutata? AKA Sun Tan Begonia?
http://www.santarosagardens.com/Begonia-soli-mutata-p/beg-sol.htm

During winter months, plants need only be watered about once monthly or as needed when the soil becomes dry about an inch or so down. Leggy plants are normally a sign of too little light. You can cut them back some and begin giving the plants more light. Here is some additional information that should help: https://www.gardeningknowhow.com/ornamental/flowers/geranium/leggy-geranium.htm, https://www.gardeningknowhow.com/ornamental/flowers/begonia/wintering-begonias-overwintering-a-begonia-in-cold-climates.htm, https://www.gardeningknowhow.com/ornamental/flowers/geranium/how-to-save-geraniums-over-the-winter.htm