power spray does help in removing old paint and also make a big mess on the surrounding when the water and old paint flying around, make sure your neighbor are okay with it

make sure you have ladder that can climb high enough to reach those places you want to paint

the steps will be:
1. scrub old paint with scraper or high pressure water spray
2. fix holes, remove old wall plug/nails/screws
3. thoroughly clean up and wipe the wall with water/thinner/acid/cleaner, make sure the surface is as clean as possible
4. mask and cover the areas that you dont want to paint with masking tapes
5. paint 1 or 2 coat of primer if you want longer lasting paint, if you painting on top of existing paint then maybe no need
6. if you change the color from light color to dark color or almost same color, you can directly paint the final paint, minimum 2 coat
    6.1 if you change the color from dark to light color, paint a layer of white/grey acrylic emulsion to cover existing color, minimum 1 coat then apply final paint, minimum 2 coat
7. wipe off leftover paint at undesired spots, and cleanup surrounding (this step is very exhausting)

if you think you cant do the step above then hire someone else to do it, terrace house need to climb to roof of first floor to paint 2nd floor, make sure the roof is in good condition for you to stand on top and you have long enough stick for the roller to reach higher spot

do remember to talk to your neighbor about it and whether they are okay with it, especially the part of the wall at the porch that separate between you and the neighbor

hope that helps