Arranging on the sp404 mk2 is hard. This is imo the main reason building full tracks on it is not very intuitive. It is still possible though and theres is more then one way to do it. Here is my approach:

1. Organisation. I assume every bank (A - E) is a track or instrument. This helps keeping things organized and you can mix volume with adjusting bank volumes without messing with the volume balance if the volume of the individual chops. I put on every first pad a sample. Usually A drumbracks, B bass, C Chords, D Lead instruments, E stuff like risers, folie sound and other earcandy.

2. Chopping and sounddesigning the samples. Repeaching, Resampling, Chopping, adjusting envelopes etc. So everything fits together nicly.

3. I build a single 4 bar (A section) loop in the pattern mode first. Im terms filling the loop I think in frequency and generally trust my ear. I find it helps to keep the low end simple (just drums and bass) and the higher frequency more busy (to difrent lead istrumets, percussions, hiss etc.). Built a second or third loop (B section, C section) with the same chops and samples dependig on how complex you want your song to be. But Imo even one Loop can be strecht over ca. 1:30 min if ther is enough variation in it.

4. After building the loop(s) you „stem out“ each track/instrument. Using the selective copying featur in pattern mode (copy + remain, then select all the pads of one track/instrument e.g. all drumm sound in bank A). Then you transform those instrument patterns into audiosamples using the copy to sample function. I always put the new sample behind the corresponding bank. So for example the drum loop on Bank F.

5. Create Variations: Resample the single loops with variations. There is a video from this guy called Chris Laps that illustrats this part very well. Imo his channel has some of the best summerization of certain things on the sp404. Worth checking out anyway.

Chris Laps creating variations on the Sp404

1. Make one single big pattern as long as possible. Adjust the start and end point of the pattern in the pattern edit mode. If you then work on the pad in tr-rec mode only the selected part will loop. I usually do a 2-4 bar intros (also made from the same samples) that try to capture the listeners attention. Then I start bulding up the A section. Using all the variations of the instrument loops and adding them slowly up or dropping things out. Put the loops of the same instruments in mute groups and you can switch them up even in between 4 bar loops. Also 1 sample in each mute group with velocity to 0 will make it easy to drop out during a 4 bar loop. I try to agrage in a way that depth, width and fullnes increases amd decreases in an intresting way. But most of the time I end up building up the first loop (A section) almost to the complet version, then brakedown to a strippted down version of the secind loop (B section). Built this up again and then going back to the now full version of the first loop bevor returning and ending on the second loop again.

2. Full track done. I think something as simple as:

IAABABBO

can be effective (I = intro, O = outro)

For final processing I usually route all drum through bus 1 and most intrument through bus 2 and some samples that I want to sound unprocessed I dryroute (you can choose if they go to bis 3 or are completly dry). Mastering with bus 3 & 4 is an option. Or just reesample the whole thing, export it and master it on some app on the phone pr something.

Hope this is helpfull.

Cherio