From Orlando Florida, Walt Disney World:

Take the I-4W and merge onto Florida's South Turnpike via Exit 77 toward Miami (portions toll).
From there take the SR-706 Exit (exit 116) toward Jupiter.
Head left onto FL-706E and merge onto the I-95S toward West Palm Beach.
Exit at Miami Ave (exit 2C) on the left toward Downtown/Biscayne Blvd/Brickell Ave.
Then take the US-1N ramp toward Biscayne Blvd.
Take the SE 1 St Ave ramp and you will be in Miami, Florida.

From Palm Beach Florida:

Take the I-95 South toward Miami and exit at the Miami Ave exit (exit 2C) on the left toward Downtown/Biscayne Blvd/Brickell Ave.
From there you can take the US-1 N ramp toward Biscayne Blvd and then take the SE 1 St Ave ramp.