some pics. of your carb and what you wondering about would be very helpful.
But, al may be right. If you can not get the slide into the carb. look at the slide. It will have 2 notches at the bottom on the sides. one will be longer than the other.
Line the longer notch up with the pin that is on the inside of the carb, on the right side.
you will have to either look into the top of the carb, or feel inside it to find the pin.
Make sure that the slot in the slide is lined up with the pin, and the slide will go all the way into the carb and bottom out. the slide will slide into the carb smoothly when the pin is lined up with the slot. Make sure that the needle goes into the hole in the inside, bottom of the carb.
the slide will go into the carb several different ways, bit only 1 way is correct.