Don't open the package until you are in total darkness!
Some films have an outer package as well as an inner can or other package, with a light-tight bag inside that.
Some films just have an outer package with a light-tight bag inside that.
Before heading into the dark, examine your loader carefully, paying particular attention to which way the film comes off the long roll - clockwise or counter-clockwise - before heading for the film gate. You want to make sure that when you open the inner bag, you sense which way the film comes off the roll, and make sure that you put it in the way that the loader requires.
There will most likely be a bit of tape on the end of the roll which you will have to release in order to feed the end where it is to go.
Also examine how the centre core that should be part of the roll fits into the loader. If there is a core still there from the last film, be sure to remove it.
It isn't very difficult to do this, but it helps to have a picture in your mind of how things should go. It might help to turn off the light and then familiarize yourself how the various parts of the loader feel and move when you can't see them.
I would recommend doing this in something like a large darkroom tray sitting on the top of your counter.