I retired only last week as a Cardiac Physiologist who specialise in Pacing.
If it's an Anti AF pacemaker, they need to turn the Therapies on, normally at first check as long as you are on a Anticoagulant.
It can be set to Pace 100%, tends to be AAI, that mean pacing the Atrium only, that is fine as its a copy of Physiologically normal, helps stop AF kicking in.
Driving is after 1 week for a Normal Pacemaker, only if you have a ICD (Defibrillator) then it's first 6 months.
The reason no over the head Arm movement, you don't want the leads to move.
The Device should last about 12 - 15 years but the wires are used many times, so they have to be spot on.
You will be fine and probably after a while forget its there.
I expect you will get a Home Monitor or depending on Manufacturer use your Smart phone for transmitting data to the clinic.
You should have been sent home with information, if unsure contact your Pacing clinic
We are all a friendly bunch in Pacing. To run a clinic the team will know there subject inside out.
Take care