Welcome Bruce, people wishing to return to film are always welcome!
I have Fujimoto as well (different model) and there is precious little information, spare parts or accessories to be had anywhere, including that auction site. Your enlarger is designed for colour enlargements, which is not to say it will not work well for B&W; I print exclusively B&W with mine. The three coloured dials are for adjusting colour balance in colour printing or in changing contrast grades in B&W printing - more red means more contrast, more yellow means less contrast. Blue can be used a primitive neutral density filter but I generally ignore mine. That said, I found a dedicated filter set more accurate than the dials and less risk of movement if doing any split grade printing (that's a different lesson). If you want to use the dials, most papers/paper developers have a set of numbers to follow for contrast control. They say if using a Bessler enlarger, grade 2 is 45 yellow and 23 red; if using a Leitz enlarger, grade 2 is 37 yellow and 65 red. Follow the instructions for Kodak enlargers (which are the closest), put it on grade 2 for a normal contrast and then it is experimentation from there.
As to not blowing a fortune on consumables, well, good luck with that. Enlarging is very much an art as opposed to a strict science and as such takes much practice to master. The only way to learn is to do it and make mistakes. If you can take a class from a local art guild or community college, or even find someone to mentor you along, it is never money wasted. Ansel Adams book "The Print" is essential reading as long as you realize he is Ansel Adams and you are not; yes he is the master but you do not have to try and copy everything he does. Rather glean as much as you can and make it your own, Adams was never about people slavishly adhering to his vision or his exact measurements/methods.
The step to larger negatives would need a different negative holder and a different enlarging lens to use your current enlarger. A good 80mm enlarging lens can usually be had for under $100 on the auction site but it pays to buy the best you can afford; a good lens will last a lifetime and nobody has every complained something was too well constructed. Negative holders for Fujimoto's are rarer than leprechauns holding hen's teeth; I am working on some cutting some stiff foam core to the necessary size and then placing glass on top to hold the negative in place. Hopefully I can get some better one's made shortly by a handy brother. Most other brands do not fit in the Fujimoto since rear of the holder has less room than other enlargers. A Yashica or Rolliflex is a great way to get into medium format on a budget. When you are ready to move up to something else, you will know it.