This particular project you might be able to get away without soldering if you use a breakout / expansion board like shown and just screw terminal down the wires. If you are feeling a bit more ambitious, you could design a PCB and have it fabricated for you by a service such as jlcpcb or pcbway
Should you still require soldering:
There are soldering stations, irons and guns that have automatic or trigger pull solder feed which can help with single handed operation - the cheaper feed solder guns will do well for something larger like through hole for simple projects like this. Id get some heavy weights, some kind of board stand/clamps, and kapton tape in a heavy / mounted to desk holder do you can pull tape off and use it to put on the board to hold things down / together / insulate other parts from slipping with the iron tip.
If you are just doing wire to wire joints, there are some heat shrink solder couplings that you can put on like its heat shrink over twisted wires and heating it over 150C with a heat gun will solder it together (e.g. electriduct).
I haven't personally had much luck with helping hands but ymmv. Soldering mat is good for spilled solder drops or if you accidentally hit the tip on the table. Solder flux (get in a syringe or squeeze bottle) helps a ton with getting a good joint. Also, some isopropyl alcohol and cotton swabs / a rag / a toothbrush are good for cleaning the flux off once you are done - if you dont do this, the joint can corrode down the line. You will also want a fume extractor; basically a fan with a carbon filter, similar to an air purifier. This will keep the flux fumes out of your face and lungs.
A hotplate and some tweezers could also help with surface mount stuff since you can just use the weights to hold it down and poke at stuff while letting the hotplate do the heating /soldering
To sum it up
Things you WILL need to solder:
- solder (leaded probably better; just wash hands)
- flux (syringe or squeeze bottle)
- soldering iron/ gun (perhaps with wire feed)
- some kind of stand/weights for holding the boards / wires
- tweezers
- fume extractor
Things I think would really help:
- silicone mat
- isopropyl alcohol and swabs / rag / tissues
- kapton tape (or other polyamide tape, the orangey stuff) and a dispenser / holder
- normal heatshrink tubing/insulation
Nice to have but might not be necessary:
- hotplate
- heatshrink solder couplings

