No handling the snake until it's settled in & feeding reliably (at least 3+ times for a hatchling- more is better, safer). Weighing a snake IS "handling"...don't do it! The time to weigh was right when you got him home & had to handle anyway. After that, not until he's settled in & feeding, or you can put him off eating at all. Eating is "job #1". Do NOT handle.
Many new snakes (of any age) won't eat right away, in the first week or more. They need time, & LOTS of privacy.
Feed EXACTLY what the snake was eating before you got them- make no changes until they're feeding reliably. If live, then feed live. If mouse, feed mouse. If rat, feed rat, as rodents all smell & (presumably) taste different.
Hatchlings are still learning & need to focus on just being a snake- feeling safe & secure, & learning to deal with prey- NOT with humans. So try to stay out of their way- keep their enclosure in a quiet place, block their "view" if needed. Avoid making adjustments to their home unless essential- the time to do that was before the snake arrived. Make sure the hides are the right size so the snake feels hidden.
If food is refused, don't keep offering right away- that adds to their stress & almost guarantees a failure. For a thin hatchling, wait 4-5 days before a retry; otherwise, wait a week or more before you try to feed again. Feed only at night, in dim light. Try not to be noticeable.