It's not the seed
but the flower
spike for the bananas. Once the embryo fruit stop forming the flower
is cut off, though this is not necessary.Just hang your bunch in a warm place out of direct sunlight and they will ripen.
The trunk which provided your bunch of bananas will now die and if cut off just below the leaves will supply moisture to the newly growing
"suckers" forming at the base of the clump. There are often a number of suckers at different stages of growth, these should be thinned out to having 3 plants
per clump. One bearing fruit, one half grown and one sucker.
To remove suckers from the clump use a sharp spade and slice vertically down ensuring some roots are removed with the sucker. There are some which have wide rounded leaves and others which will have a narrow pointed leaf at the suckering stage. Keep the narrow ones, discard the others. Maybe approach your neighbour for a sucker to start a clump with.