Is it easy to swap Gb RAM on a laptop?
It depends on what kind of laptop and what kind of CPU / chip it is. With an Intel / AMD laptop it is very likely very easy to change, but with the new M1 Macs or laptops with an ARM chip it is impossible.
Usually yes, but the laptop also depends.
It's best to have a look beforehand. There should be a description in the operating instructions and it is not uncommon for YouTube to have video instructions
Asus laptop
Asus laptop f555
Since it is very likely easy, just buy a certain laptop ram and unscrew it. The best thing to do is to look at yt and preferably directly to your model
Most of the time it is very easy to find the small flap, but be careful: The RAMS arrive in special packaging, because static electricity is fatal. So it's best to avoid touching any of the gold-plated contacts with your fingers, then it should work too.