Congrats on the enlarger.
The Vivitar VHE lens is supposed to be a GOOD lens. I think it was made by Schnieder. Do a google search on it. The VHE was the high-end lens, not the cheap lens I used in high school.
Get the manual and STUDY it.
Some enlargers are querky, and the 23C is one of them. You adjust the condenser position with the upper bellows. Querky but less expensive than having condensers for each format.
Glass or glassless negative carrier, each person has their preference. I suggest starting with whatever you have (probably glassless) and then determining if you want to go with a glass carrier.
The filter drawer is where you would put the Multi Contrast filters and a heat absorbing (HA) filter. Although you don't really need a HA filter. If you want a HA filter, you can order one from Beseler or find a company that sells HA glass and have them cut a piece for you.
I recommend that you get 2 spare bulbs for the enlarger. That way if the bulb burns out, you can immediately replace the bulb. With local photo shops disappearing, if the bulb in the enlarger burns out, you will have to wait DAYS for a new bulb to be shipped to you.
Enjoy your new toy.