Hello Prateek,
You can go for any of the two methods you mentioned provided you have right stuff for it. Using a Y connector, most easy one.
Just connect your servo to the Y connector and plug it in channel 1. If you don't have a Y connector then order one for you or otherwise what I usually prefer, make one for yourself. You'll be needing just few servo extension cables(Generally, three). Lots and lots of videos are there on youtube.
OR
you could use mixing feature if you have a programmable radio. In this, one servo goes to channel 1 and the other to channel 6(usually in almost every brand) and then refer the manual for mixing.