Hi Terry,
There is a short cut that misses out the town, but really it is too complicated to explain.
The easiest way is really to turn right when you leave the airport (there is a sign for Centre & Port). Continue until you have the sea directly in front of you. Turn left here, keep on this road with the sea on your right side. Follow the signs for the Port, you will come onto a one-way system passing through arches. Continuing through the arches eventually takes you past the Ferry port on your right , the Fort is on your left.
Keep on this road until you see this sign for the dual carriageway...
Turn right at this sign and continue on for approximately (!) 10 klms until you see this overhead sign....
And here is it in close up....
Turn right as indicated for the Sidari road.
You have Harolds directions from there to Arillas, but if there is anything else I can help with just ask.
I hope the above directions have not confused you more.
Eileenx