Make sure the ends are trimmed square with suitable cutters (Dremel, Xuron etc).
Put rail joiners on both rails of one pice of track - it may help to lightly pin it in place with drawing pins.
Slide the second piece of track into place - it may help to pull each rail into the joiner carefully with small pliers.
Use a Tracksetta guide of suitable radius across the joint to help avoid kinks.
Don't forget to either remove a full sleeper on each abutting section or carefully slice off the rail chairs on each end sleeper of the two abutting sections track pieces. This allows the fishplate (rail joiner) to be fitted.
If you remove sleepers, cut off the rail chairs and slide them back under the track once it is laid to keep the sleeper spacing appearance correct
Mr Bones wrote: ↑Mon Jul 22, 2019 8:20 pm
If you are going to use that method, then this guy explains how it's done.
That method I find is the best especially I you have to play about and adjust the curve however you do have to cut the flexicurve square at some point such as joining onto a turnout but you really need to be happy with your curved section before committing otherwise you find yourself cutting back lengths of track with every adjustment or worse still patching in short sections.