With the opener disconnected from the door, can you open & close it
EASILY by hand?

If it closes by hand with some difficultly (you have to puch it closed)
but shoots up; you have too much spring force & it needs to be reduced.

Openers are not any stronger than people, both require a well balanced
door system.

A well balanced door takes very little effort to move.
Most "garage door opener problems" are door related not opener related,

If you're not super handy / mechanically inclined don't mess with it.

The spring forces are high & they can you hurt badly.

If the door is well balanced but the opener still reverses you need
more down force; some openers have a screw adjustment for opening &
closoign force.
So also have close & open limits on the rail or internal to the opener.

After any adjustments you need to do the "closing on obstruction" test.



cheers
Bob