i've heard about rodinol, no offense but if this is your first ever, stick to the most tried and true,most universal, the one that works really well with just about everything: D-76 or the same thing from Ilford ID11, which I believe comes in liquid.

follow the instructions, you cannot go wrong. I am not a bulk user, so I use it as a one-shot stock diluted 1:1 with water and toss it -- a gallon lasts a long time, no complicated mixing formulae...