How can I use plain TeX &
metafont to attain my own font-style, i.e. I want to type the words I write by my hand.
plain tex doesn't come into it much (you can use these things with any tex or pdftex format).
there are several metafont "handwriting" fonts on the archive. the earliest i recall is peter vanroose's, which you can download from ctan (or browse the ctan directory, to get a feel for what it involves. (unfortunately, it's not distributed with tex live or miktex.)
personally, i never got around to "proper" fonts with metafont, having stumbled a lot with creating a symbol font for a place i worked at.