Bike Brakes Sticking

87 honda shadow 700 brakes sticking?

I have a 87 honda shadow vt700c and im having trouble with the front brakes. I was going down the road and the front brakes locked up to the point that smoke was coming off the front rotor. Once the brakes cooled down i was able to move the bike. I can still hear the brakes rubbing against the rotor. This is my first bike and im not sure where to start to work on them. Any help would be great.

Most common – caliper rebuild is required.

Gunk builds up under the piston seal.
The seal squeezes tighter against the piston, preventing it from retracting back into the caliper.
Dirty, or pot marked from rust, pistons – again preventing the pistons from retracting back into the caliper.

Trek 6000 ( with upgrades)