I'm only recently starting to research bonsai and all that goes into it. Currently it is winter but I am moving to a new house and want to take up gardening. I'm planning on growing from seeds and am wondering if I should use stratification or if it would be more advisable to wait until next autumn to begin with the planting. Also, would having multiple growing at the same time be smart or should I focus my attention on a singular tree?

You will give up long before you have anything big enough to use to think about training. Buy 4 or 5 year old plants much easier and at least you will know they are alive

CooperPB wrote:

I'm planning on growing from seeds and am wondering if I should use stratification

Depends on the species. Continue doing research.

Auk wrote:

CooperPB wrote:

I'm planning on growing from seeds and am wondering if I should use stratification

Depends on the species. Continue doing research.

I was planning on the Amur Maple as it's suited well to the location and climate I live in.

All Acers (?) are deciduous trees, adjusted to growing in temperate climate with a distinct cold period. So yes. They need a cold period to germinate.
Also see www.growingbonsai.net/breaking-dormancy-by-species/
Do note the previous post though. It will take long before this is fun to play with, so you might want to (also) buy bigger stock.