I have put my new caliper on, the piston has not adjusted itself yet. Is that done by pulling the handbrake?
I will read some more.
Other side to put on tomorrow.
If replacing caliper but not pads
Wind caliper out until pads are snug
If wound out too far, wind back at least one turn then wind out again.
If new pads (may as well while doing caliper) wind all way back should be a snug fit for pads on disc.
In either case, bolt everything up once happy.
Make sure hand brake cables are in.
Lever arm should be back on rest, cables may be a little loose. That's okay.
Pump brake pedal a few times to push piston out
Then and only then, operate handbrake to let the self adjust operate.