I over wintered my plant indoors and now it has many many vines sprouting out all over. Should I trim these off? It never developed any seed pods. I would like to start new cuttings as I can't find any new plants in my town.
Trimming a Mandevilla Plant
This article talks about mandevillas and overwintering in the house. https://www.gardeningknowhow.com/ornamental/vines/mandevilla/growing-mandevilla-indoors.htm
Unless you need to keep the plant to a small size, you should probably let the new vines grow. If you put it outside for the summer, it certainly could flower.
Here is information on propagating these plants: https://www.gardeningknowhow.com/ornamental/vines/mandevilla/mandevilla-propagation.htm