使用 Room, Jetpack Compose 和 Paging 3 一起加载数据的步骤如下：

1. 在项目的 build.gradle 文件中添加以下依赖：

// Jetpack Compose
implementation "androidx.compose.ui:ui:1.0.0"
implementation "androidx.compose.material:material:1.0.0"
implementation "androidx.compose.runtime:runtime-livedata:1.0.0"

// Room
implementation "androidx.room:room-runtime:2.3.0"
kapt "androidx.room:room-compiler:2.3.0"

// Paging 3
implementation "androidx.paging:paging-compose:1.0.0"

2. 创建 Room 数据库和数据访问对象（Dao）。在 Dao 中编写查询语句，例如：

@Dao
interface UserDao {
    @Query("SELECT * FROM users")
    fun getUsers(): PagingSource<Int, User>

    @Insert(onConflict = OnConflictStrategy.REPLACE)
    suspend fun insertUsers(users: List<User>)
}

3. 在应用程序的入口处初始化 Room 数据库：

val database = Room.databaseBuilder(context, AppDatabase::class.java, "database-name").build()

4. 创建数据源（PagingSource）：

class UserPagingSource(private val userDao: UserDao) : PagingSource<Int, User>() {
    override suspend fun load(params: LoadParams<Int>): LoadResult<Int, User> {
        val page = params.key ?: 1
        val pageSize = params.loadSize
        val offset = (page - 1) * pageSize

        val users = userDao.getUsers(offset, pageSize)
        val prevKey = if (page == 1) null else page - 1
        val nextKey = if (users.isEmpty()) null else page + 1

        return LoadResult.Page(users, prevKey, nextKey)
    }
}

5. 创建分页数据流（Flow）：

fun getUsers(): Flow<PagingData<User>> {
    val userDao = database.userDao()
    val pagingSourceFactory = { userDao.getUsers() }
    val config = PagingConfig(pageSize = 20)

    return Pager(config, pagingSourceFactory).flow
}

6. 在 Jetpack Compose 中使用分页数据流：

val userList = viewModel.getUsers().collectAsLazyPagingItems()

LazyColumn {
    items(userList) { user ->
        Text(user.name)
    }
    userList.apply {
        when {
            loadState.refresh is LoadState.Loading -> {
                item {
                    CircularProgressIndicator()
                }
            }
            loadState.append is LoadState.Loading -> {
                item {
                    LoadStateFooter()
                }
            }
            loadState.refresh is LoadState.Error -> {
                // Handle error
            }
            loadState.append is LoadState.Error -> {
                // Handle error
            }
        }
    }
}

这是一个简单的示例，你可以根据自己的需求进行修改和拓展。