An electric bike makes a first tour feel possible, and it also makes it easy to ride further than you can get home. The motor hides the hills on the way out. It does not hide an empty battery on the way back, or a bag that is too heavy for the rack you fitted the night before.
Start with a distance you could ride without the motor
For a first overnight, pick a loop or an out-and-back you could finish unassisted if the battery died at lunch. That is often 40 to 60 miles in a day on lanes, not a 90-mile coast-to-coast you saw online. Use the motor for the hills and the headwind. Keep a reserve. If the display is still showing a comfortable charge at the halfway cafe, the route was the right size.
Charge before you need to
Know where the battery comes off the bike, and take the charger in a place you can reach without unpacking the tent. A cafe that will let you plug in for an hour is a better plan than hoping the pub has a socket by the bed. Tell the place you are staying that you need to charge a bike battery. Most will say yes. Some have nowhere safe to leave the bike, which matters more than the socket.
Pack for the bike, not for a car
One change of clothes, a layer for the rain, tools that match the bolts on your rack, and a lock you will actually use when you buy lunch. An e-bike is a theft target outside a cafe. Lock the frame to something solid, and do not leave the battery on the bike while you eat if you can take it with you. The rest of the kit can wait for the second trip.
Choose the night first
Book the stop before you fall in love with a scenic lane. A published cycle route that arrives after dark, at a pub that stopped doing rooms, is how first tours go wrong. Arrive with daylight left to walk around. The motor got you there. The evening is the part you will remember.
Ride a short first tour, charge on purpose, and lock the bike. The range on the sticker is a ceiling, not a plan.