I've actually done this myself. The first time I was not successful. The second time I was successful.
There are a few things that go into this.
Planning -- finding a transit near you
Equipment -- what you'll need and/or considerations for what would work
Exposure -- considerations of the ISS that will influence your exposure
Panorama applications can usually auto-align a stack of photos since this is a special case of the adjustments needs for correct stitching.
For instance how you can use Hugin for this is shown here.
To get to the interface used in the guide, go to View -> Panorama editor. Also make sure Interface in the menu bar is set to Expert, or the Remapped Images ...
The starters the easiest is simply to assemble images into a video. This will already give you a time-lapse. Any tool that can create a video from images can do this. ffmpeg is a popular free utility with lots of options but will give you something without much trouble. See this SuperUser question for details and other options.
The second level is to align ...
The interval-timer on Canon bodies that have the built-in feature work a bit different than an external interval timer.
External Interval Timer
An external timer can either use one of the camera's fixed shutter speeds... or can use bulb mode. In bulb mode, the timer is effectively "holding the shutter button" and releasing it to end the exposure. ...
qDslrDashboard's "Auto Holy Grail" mode does bulb ramping from iOS over a wi-fi connection with your 77D. The iOS port of it is called ControlMyCamera and is a beta that requires TestFlight to install.
Bulb ramping is where the exposure settings are automatically adjusted between images in a timelapse sequence to maintain overall exposure in ...