Hi, I fixed up a neglected Dutch Town bike that was originally elecric and it's very nice to ride. I'm sure yours can be converted to electric.
The easy place to fit the battery is on a rack above the rear wheel - anywhere else needs thinking about due to the shape of the frame, and you don't want it where your feet will catch it when you are getting on or off.
Some photos, the battery is hidden under the panniers when I go shopping (I like that's it's not obvious)
https://www.pedelecs.co.uk/forum/threads/kemp-starley-dutch-town-bike-out-of-hibernation.37181/
Thoughts: mine has the motor in the front wheel and the battery on a rack over the back wheel so the extra weight is balanced nicely between front & back. Controls on the handlebar are very simple (originally a low/medium/high power switch, now changed to a twist-grip throttle). The wires are neatly hidden inside the frame (easy as the frame tubes are so large - maybe not so easy on yours).
I also have a bike with the battery at the rear and the motor in the back wheel, the bike is very tail-heavy unlike the Dutch bike.
Make sure you buy the correct size wheel when you buy the electric kit, someone had tried to fit the wrong size electric wheel to the one I got - very silly and it could never work properly.
The same person had bought a very cheap electric kit, it works but isn't very nice to use, suggest you pay attention to the suggestions from experienced folk here so you get a nicer bike at the end.
I've found I'm using the bike a lot more now the electrics are working properly, and its a lot easier to go on longer trips. I'm sure you won't regret it if you get a decent electic kit.