SRM, with his experience, gives the best advice.
We learnt to sail cats, sailing off a beach. Face into the wind, rig the boat, do the final checks, and go.
It was a shock to us when we moved downriver to a Club with a dock. (
http://www.nsc.ca)
Now this is a dinghy boat dock, with rubber 'rub' strips at exactly the right height, so bear that in mind as you read.
Plus, this is a floating dock, and there are no tides to consider.
To make things even simpler, our prevailing winds blow 'down the ramp', so usually we raise the sails on land, and wheel our catamaran down the ramp into the water and tie up to the dock.
Our righting line doubles as the painter.
At that point, we attach the main blocks and jib clew, lower the rudders, do our final check, and sail away.
The Albacores and 505's and Lasers do the same.
When the winds blow from another direction, life can get very interesting.
Often, we will slide the mainsail into the sail track, raise it about 24" or 36", and stop there. The jib is raised on land, and flapping freely.
Then we launch, secure the cat to the dock in a 'good' orientation to the wind, and continue the raise from there.
You should also be aware that when you launch, you have to return.
Sailing back to a beach is usually easy peasy - unlock the rudders and sail up onto the sand.
Sailing back to a dock can be a learning experience, especially if you are new to sailing and new to your boat.
In 'normal' winds, docking is easy. However, if the wind is the 'wrong' way, life again becomes interesting.
The water is only about 5' deep at our dock, and in the first year at our Club, a number of times, I had to jump off the cat and physically stop it from bashing into the dock.
Looking back, it helped me grow my sailing skills, and I continue to learn every time we go out.
We've been tourists in Portland, and we are jealous of the mighty fine sailing you enjoy on the Columbia River.
As I recall, the wind mostly blows upriver, so you may wish to inspect the launch points to check out the orientation.
Also, check out local sailing clubs, and see if you can join up for a 'learn to sail' program in Portland or up at Cascade Locks, or in Hood.
Good winds!