Well, good for you, I'm sure you'll do fine
I am far from an expert but I have found that a grooming noose with a suction cup on the end helps keep mine still while on the counter and/or in the sink - I just attach it to the tile wall.
I also groom them every week before their bath - or I should say I go through the 'motions' of grooming them every week. Regardless of whether they need their nails trimmed or hair cut I do the whole routine and just lightly trim. I found that now they are very calm and there are never any 'surprises' for them because they know the clippers, scissors and nail trimmer will come out every single week