Hi Alexis - welcome to APUG and the wonderful world of the darkroom.
All the advice above is good. I'll add a book recommendation: Henry Horenstein's "Black & White Photography - A Basic Manual"
And two links:
1) Kodak: http://wwwtr.kodak.com/global/en/pro...bs/aj3/aj3.pdf
2) Ilford: http://www.ilfordphoto.com/applications/page.asp?n=9
You can also look up ROL, one of the members here. He has a number of useful materials on his website.
The Kodak and Ilford materials referred to in the above links are good (where still available) but you aren't limited to them - there is still choice available.
The "Nikon 6x7" you refer to may actually be a "Nikor 6x7" enlarger. I think you might find it hard to source parts and accessories for it.
EDIT: looks like ROL beat me to it
PS have fun!