You have two choices.

Start the porch at the current roof line which will make for a low porch and perhaps dark inside the cabin.

Or start the porch roof further back on your existing roof which will allow you to have a roof that is no lower than your current roof line. You can see that the pitch of your roof will 'swoop' or angle over the porch.

If you want the porch on the right side gable end: extend the current gable roof line out. It will make a nice high ceilinged, pleasant space. Obviously, columns will be needed for support.

Make sure you make it at least 6 feet deep. Any shallower and humans aren't very comfortable using it. Deeper is better!

I would have it attach similar to this, note just the roof attachment. However, I wouldn't add all the railing since this is more of a back deck feel and the example is an entry.

Mainly it all depends on the budget, from there you can plan what you need and want to add. If you need to turn the attic to living space you can do something like this

Thank you everyone! This is a great start and I really appreciate the help and photos for inspiration.