Arthurs seat is the summit of the extinct Volcano in Edinburgh, its found in Holyrood park just off the bottom of the Royal mile near the palace. Àrd-Na-Said is actually the old Gaelic term for Arthurs seat, which translates to heights of Arrows, perhaps from Archers seat ?
There are several ways to get up to the summit of Arthurs seat, and it may seem like a daunting hike but this is definitely a hike for beginners if you take your time, and it's worth it when your at the top.
My favourite time to go is between may & September because of all the blossom the hills are covered in these beautiful yellow bushy flowers. Also my favourite time of day to go is during the sunset, which is closer to 10pm in June, its a beautiful way to end the day and see all the wonders of Edinburgh from above.
The longest but most scenic way is to start from the "official" trail beginning near Holyrood Palace. This brings you up past the old remains of St Anthony's chapel, and the remains of a small well. walking through the blossom you twist your way slowly up to the top.
otherwise, the quickest way from the guest house, if your in just for the view from the top is to go to the road by the common wealth pool side and follow that up util you get to Dunsapie loch, then you will be able to see the summit of Arthurs seat directly behind you if you face the loch. and just walk straight up. its a slow 20 minute climb but the views are worth it at the top.
Make sure to bring a sweater or wind braker as the winds can feel quite strong at the top and bring the temperature down.