I depends on your needs - a study/sewing room, sitting area, playroom? Decide needs first.

It doesn’t look very wide so you might be best with bench seats for your table. Or a smaller table and strait legged chairs.
There appears to be lots or walkways through the rest of the space which doesn’t leave much space fo furniture elsewhere. Some potplants would be a good addition. Can you post a scale plan with measurements

make a plan of the room marking correct size and location of all doors and windows (inlcuding height and distance above the floor and where the doors lead to) and location of dining table but there looks like there may be enough space for a narrow divan bed with side table under the window, short bookshelves along the full length of the timber clad walls a single small lounge chair tucked into the corner near the glass doors, add some artworks along the new painted timber walls, indoor plants and some new lighting

It is actually a holiday house - so the focus is on relaxation and fun! Here is a plan of the space. As you can see it is quite narrow but very long - Just not sure how to furnish, beside a dining space at one end.

Lots of options.

to me it looks like this area is a high traffic zone, leading in and out of a lot of rooms, i would possible place a long runner rug focally leading upto a low cabinet below the window with a tall plant on the side. But ofcourse depending on your needs spatially too... i would do a study at the end of the corridor or a cozy reading chair with a floor lamp too.

These spaces generally do okay as mud rooms or offices, since they are a transitional space between indoor and outdoor. The screened porch idea is also rather good. I wouldn't try and furnish it like a regular room because of it's size and shape. It will always look like what it is, a covered in verandah. Since it's a holiday let I would build in coat racks, boot rack and perhaps a cushioned storage box for toys, games. At the most I would place a couple of rattan chairs our there and a coffee table with some books on it for a peaceful hideaway.

How lucky you are to have such a great space, keeping it understated by not overcrowding will look fabulous, you could add a swing seat

For a cosy retreat, some gorgeous statement chairs, sometimes less is more to obtain a wow look.

You guys are amazing - lots of great ideas here! Thank you so much. Once it is finished I will post another pic.