A simple magfloat will get rid of them off the glass. Like rick said, common for new tanks. I'm more focused on the anemone and lettuce slugs. What is your lighting? A nem needs good lighting. As for the lettuce slugs, if they don't get fed enough and die they will pollute your tank with toxins. Something to keep in mind.
Diatoms can take longer to get rid of. I think mine lasted 3 weeks on my current tank. They'll go away once they consume the silicates in your tank. You can clean it, or leave it in there until it goes away. Up to you.