Just guessing out loud here, based on location, but you have a couple of options.
Geologically, the southern coastline seems to parallel the Antarctic coast - it's like South America and Africa, they almost fit together like pieces of a jigsaw puzzle. What this means is that they were joined and have split apart. What that means is that Magellanica is moving north, and probably pretty recently - in the last twenty or thirty million years or so.
Why is this important? Because that means that the mountains are going to be in the direction of movement - ie, the Mountains are going to be on the northern shores. It looks like there are two northern shores - an east and a west, both of which rise to meet in the center.
So it may only be one of the Northern shores which is mountain ranges. Possibly both, but perhaps only one. The overall slope is going to be southwards - ie, the highest average elevations will be northern, the lower elevations will be southern.
Mountain ranges are important - they get in the way of things. They block rainfall and wind carrying warm or cold air. They glaciate, and the glaciers either feed rivers, or crawl down and become ice caps.
If these are young mountains - 15 or 20 years old or less, then they'll be tall. Which means pretty fierce, and glaciated. They'll block warm winds coming off the tropic or temperate regions of the Atlantic or Indian. Which means that the land on the other side of those mountain ranges will be comparatively colder. They'll be warmed by the sun, but they won't have a gulf stream effect which makes Europe so hospitable. Coastal air will feed the glaciers, which will crawl down and slowly move south. And the southern reaches will be overall colder, with likely snowfalls heavy from the circumpolar. Which means the whole thing turns deep freeze.
You might have a southern version of Greenland there. That would suck.
But assuming you only have one of the northern coasts mountainous, that might change the equation. You'd have to check the southern wind and currents. And then have your continent drifting the opposite direction. You want the warm winds and the warm currents from the tropics coming to the coast that isn't mountainous. In that case, you'd have a good shot at a fairly warm coast, and a non-glaciated interior. You'd still get mountains with glacier caps on the other northern coast, but with a warmer interior, you'd get a lot of river systems being fed.