Useful Typst Code: Adjust the page number style, set the starting page number, and customize the heading and outline styles.

heading.typ

// set differnet name for different levels of title
#set heading(numbering: (..numbers) => {
  let level = numbers.pos().len()
  if (level == 1) {
    return numbering("第一部分", numbers.pos().at(level - 1))
  } else if (level == 2) {
    return numbering("第一章", numbers.pos().at(level - 1))
  } else if (level == 3) {
    return numbering("1.1", numbers.pos().at(level - 2), numbers.pos().at(level - 1))
  } else {
    return numbering("1.1.1", numbers.pos().at(level - 3), numbers.pos().at(level - 2), numbers.pos().at(level - 1))
  }}
)
// customize title format by defining functions
#let hd1(in_text) = {
  text(size: 18pt)[
    #align(center)[
    #heading(level: 1)[#in_text]
    #v(10pt)
    ]
  ]
}

#let hd2(in_text) = {
  text(size: 16pt)[
    #align(center)[
    #heading(level: 2)[#in_text]
    #v(5pt)
    ]
  ]
}

#let hd3(in_text) = {
  text(size: 14pt)[
    #align(left)[
    #heading(level: 3)[#in_text]
    ]
  ]
}

#let hd4(in_text) = {
  text(size: 12pt)[
    #align(left)[
    #heading(level: 4)[#in_text]
    ]
  ]
}

# use function
#outline()

#hd1("野外实习报告")

#hd2("实习目的")

#hd3("峨眉山食物")

#hd4("野外实习目的")

json_batch.typ

// suppose a json file in format:
// {
//     "1": {
//         "phylum": "Tracheophyta",
//         "genus": "Selaginella",
//         "species": "moellendorffii",
//         "infraspecies": "",
//         "family": "Selaginellaceae",
//         "kingdom": "Plantae",
//         "class": "Lycopodiopsida",
//         "order": "Selaginellales",
//         "name": "江南卷柏"
//     },
//     "2": {
//         "phylum": "Tracheophyta",
//         "genus": "Heterostemma",
//         "species": "wallichii",
//         "infraspecies": "",
//         "family": "Apocynaceae",
//         "kingdom": "Plantae",
//         "class": "Magnoliopsida",
//         "order": "Gentianales",
//         "name": "醉魂藤"
//     },
// ...
// }

// get json content according to id
#let Plant(id) = {
  let name = json("plant.json").at(id).name
  let genus = json("plant.json").at(id).genus
  let species = json("plant.json").at(id).species
  let latin_name = text(style: "oblique", font: "Arial")[#genus #species]
  text()[#name (#latin_name)] 
}
// use the context we get with image
#let PlantIMG(id, ext_caption) = {
  figure(
    image("img/植物/标本制作/"+ id + ".JPG", width: 95%), // this should be your image file name, which contains id
    caption: [
      #Plant(id)\
      #ext_caption
    ],
    supplement: none
  )
}
// use example

#PlantIMG("1", lorem(20))

#PlantIMG("2", lorem(20))

#PlantIMG("3", lorem(20))

outline.typ

// Set outline Title
#align(center)[
  #v(100pt)
  #text(size: 25pt)[
    目录
  ]
]
// Change outline style
#show outline.entry.where(
  level: 1,
): it => {
    text(size: 16pt)[#it]
}
#show outline.entry.where(
  level: 2,
): it => {
  v(2pt, weak: false)
  text(size: 15pt)[#it]
}
#show outline.entry.where(
  level: 3,
): it => {
    text(size: 14pt)[#it]
}
#show outline.entry.where(
  level: 4,
): it => {
    text(size: 13pt)[#it]
}
// Set default properties
#outline(
  title: text(size: 20pt)[],
  indent: 2em
)

page_numbers.typ

// for better showing
#set page(
  height: 0.5cm,
  width: 3cm,
)
#set text(size: 2pt)


#align(center + horizon)[
  First page
]

#pagebreak()
// set this page to the first page to use 'i' style
#set page(
  numbering: (..numbers) => {
  return numbering("i", counter(page).get().at(0) - 1)
},
)
// use odd or even page numbers
#set page(footer: locate(
  loc => if calc.even(loc.page()) {
    align(right, numbering("i", counter(page).get().at(0) - 1));
  } else {
    align(left, numbering("i", counter(page).get().at(0) - 1));
  }
))

= First level title
#align(center + horizon)[
  Second page
]
#pagebreak()

== Second level title
#align(center + horizon)[
  Third page
]

#pagebreak()
// set this page the first page to use '1' style page number
#set page(
  numbering: (..numbers) => {
  return numbering("1", counter(page).get().at(0) - 3)
},
)
// odd or even page numbers
#set page(footer: locate(
  loc => if calc.even(loc.page()) {
    align(right, numbering("1", counter(page).get().at(0) - 3));
  } else {
    align(left, numbering("1", counter(page).get().at(0) - 3));
  }
))

=== Third level title
#align(center + horizon)[
  4th page
]

#pagebreak()

#align(center + horizon)[
  5th page
]

#pagebreak()
#outline()