Hi PivBoi --
Normal line to electrified line? Basically with guts, determination, blood, sweat and tears. I can assure you it is not an easy process, at least to begin with.
Be aware there is no standardized height for the locomotive pantograph and the catenary wire. You will have to choose ones that work together.
I've done several electrified routes and layouts. A couple are DLC, some are on the Download Station. This is the latest that I'm working on, which may eventually be part of the N3V TMR2 release, if it ever comes to fruition (the TMR2 that is, not the layout). Best watched full screen and at 1080p:
I have several other videos on youtube.
It uses Download Station content by emges:
Old 1t pole -- trackside accessory.
Old 1t pole -- spline.
Old endpole -- structure.
Catenary wire -- spline.
As John suggests above, do some experimentation before you embark on a more ambitious route. Maybe set up a short route with a few curves and switches.
Good luck,
Phil