Easy. The only thing I can add is to make sure you have all your ingredients ready before you start. I lost my souffle dish and substituted a casserole dish. Prepped it with butter and finely ground parmesan. As you can see it worked just fine!
I was a little worried tacking this but it was so easy. I even got everything totally wrong! I put the whites straight into the sauce mixture instead of the yolks and so I just thought I would throw the yolks in and see how it all goes. It still rose so high above the ramikins I used and was perfect! So even if you stuff this up I think you are still good!
A classic, good place to start.