Don't forget to install the plotter.
Do the Archicad stuff first.
1. Change the pens. Read this. The PMK to use is "Standard Pen Table yada yada.PMK".
2. Page Setup. Go to File -> Page Setup. (Not Plot Setup!) At "Format For", select "WINPRINT 192.168.1.29". Select the Paper Size from the next pulldown. 18x24 is ARC C. 24x36 is ARC D. 30x42 is 30X42, not ARC E. (11x17 should be printed on the "small" printer.)
3. Master Layout Settings. For each master layout in use, click the "Settings" button (or Cmd+T with the master open). Click the Paper Size pulldown and select "Import Settings from printer" (at the top). This brings up Page Setup again. OK it, then OK the Master Layout Settings.
4. Title Block. Update the title block drawing on all the Master Layouts that are in use. (You switched the object in Archicad, right?) Move the title block drawing so the center is on the center of the paper (The layout center is detectable and represented by a little +.) In the masters, move the sheet number autotext block ("Undefined Layout Number") so the center is on the number box center hotspot.
5. Adjust Drawings. All your plans probably need to be moved. They are likely too low and to the left. Horizontally, align the right edge of the drawing with the left edge of the title block. Vertically, align the center of the drawing with the center hotspot of the layout. Do this right, so your plans stay aligned. Other drawings might need to be moved, too. Look into it. The alignment precision isn't as important with non-plans.
6. Vectorial Fills. Options -> Display Options. Switch Fills to "All Vectorial". One of the differences between plotting and printing is that fills are always Vectorial when plotting, regardless of the Display Option. For printing you have to set it right. This is an easy one to forget that will make your output instantly terrible.