I’m I doing this right, I feel like I’m not doing it right
I simply bevelled a side 2cm/30 segments, i feel like 20 would be enough.
or is there a better way of doing this. any kind of help would be appreciated.
I have been (again) away for 2 months from Blender, came back about 2 week ago (yet again…)
Cheers 
What were you going to do with the mattress next? Is it going to be seen from far away, or close up? Will it be seen at all?
If it is far away, that modelling method is fine (although finding a normal map would hugely help and I recommend doing it).
If it were for closer images, then more accurate modelling would be best. The bevel does not capture the true shape of the mattress. Usually, there is a thick seam bit that goes where the bevel is (unless it was a cheap foam mattress). Mattresses have to be stiched together somehow. In addition, bumps and textures would be seen in the mattress as its design.
Also, if you are not showing the mattress at all (putting sheets over it), then the bevel like you have done is completely fine.
