Meaning trap
get on
board transport
to enter or go onto a form of transport such as a bus, train, plane, or bike.

Don't mix these meanings
Same phrase, different job.
to enter or go onto a form of transport such as a bus, train, plane, or bike.
Another meaning of 'get on' is 'make progress'; compare the examples to keep the meanings separate.
Hear it in context
Notice where the phrase sounds natural.
We need to get on the bus before it leaves.
When I travel to work, I usually get on the subway at 8 a.m. because it's less crowded.
Fix the pattern
One small grammar move makes it sound right.
Not: I got in the bus quickly.
Say: I got on the bus quickly.
Use 'get on' for buses, trains and planes; 'get in' is for cars and taxis.
Which sounds natural?
Tap the one a native speaker would say.
'Get on' is the everyday verb for boarding; 'board the train using the rear doors' is a station announcement.
Build natural chunks
Words that usually travel with it.
get on + transport
- the bus
- the train
- a plane
- your bike
Don't confuse it
Related
Other meanings and phrases to compare.
- get on (make progress) — Another meaning of 'get on' is 'make progress'; compare the examples to keep the meanings separate.